Isabella Rossellini is in a bullish mood this morning.

"I'm always asked about age," she sighs. You can almost see the disappointment in her eyes; not this old question again. It's something she's faced for almost 20 years, since cosmetics giant Lancome ended her 14-year modelling contract in 1996 for being "too old". She was 44 at the time and still looked as ravishing as her mother, the legendary Swedish actor - and three-time Oscar-winner - Ingrid Bergman.

Even now, at 61, she would seem a perfect choice to model a miracle skin cream. Dressed in black trousers and boots, with a white blouse underneath a grey zip-up smock and a navy polka-dot scarf wrapped around her neck, her face seems in defiance of wrinkles. Her dark hair cropped boyishly, as she so often wears it, I'm reminded of the striking campaign she shot with Annie Leibovitz two years ago for the Bulgari handbag line - the Isabella Rossellini collection - she was promoting.

In that picture, Rossellini sat on a couch in a purple dress and heels, the right strap hanging loosely off her shoulder - a nod to her star-making turn in David Lynch's 1986 film Blue Velvet. While most models who switch to acting turn their backs on the fashion world, Rossellini has never been like that. "I miss modelling," she says, honestly. "I loved to work with a photographer." But, perhaps due to the Lancome incident, she is aware of the realities of an industry built on perfection.

Understandably, she's touchy on the subject. "I was a model 35 years ago. I can never be what I was 35 years ago. I don't serve the image," she says, those green eyes narrowing. "Life goes on. What do you want me to do at 61? Still be a model and try to look 25? You would respect that? I wouldn't. When I see some people doing that, I feel that person is suffering, that person doesn't feel good in her skin." Thankfully, Rossellini has learned the art of growing old gracefully.

"It'll happen to everyone," she says. "It's just natural. Life has to evolve, and what you do at 20, you cannot do at 40, and what you do at 40, you cannot do at 60. And what you do at 60, you cannot do at 80. So there are chapters in your life. And it doesn't mean you're not missing parts of it. But also there is new adventure and new things that are opening up. So it's not bad to grow old. But some of the things you do that you liked don't come back."

Her new adventures are somewhat exciting, however. Seven years ago, she left New York and moved to Bellport, Long Island, buying 30 acres of land which she has gradually converted into a working organic farm. "I don't grow it - I have a farmer that grows it - but it is my land. Completely self-sustaining. The farm was part of a retirement plan. Not because I can eat my own salad - I have money for that - but a different plan."

Partly, it was a plan to keep active. "Film and fashion - it's for younger people. There's more room for younger people," she says. Partly, it was a way to escape the prying eyes of a city that never sleeps. Her mother did the same years earlier, returning to Europe to live a quieter life after a spell in Hollywood. And it also allowed her to keep animals. "When I lived in the city, you can only have dogs or cats. But now I live in the country, and I have chickens, rabbits, pigs."

She's even raised seeing-eye dogs for the Guide Dog Foundation, part of her continuing fascination with the natural world. A few years ago, she went back to education, taking a degree in animal studies at New York University. It came about because her acting roles began to shift from leads to supporting roles. "You do have a lot of time on your hands. That's why I went back to university. Now university has become so important, it might be 'There's a film in November; I have exams, I can't do it.' You have to prioritise."

It wasn't the only reason, however. Nine years ago, Rossellini began making short films. The first was My Dad Is 100 Years Old, which she wrote as a tribute to her father, Roberto Rossellini, the Italian filmmaker frequently considered the father of neo-realist cinema. She starred in the Guy Maddin-directed short, dressing up as such landmark directors as Alfred Hitchcock and Federico Fellini. Bought by Robert Redford's Sundance Channel, it then led to Redford asking her to shoot an internet series. Her suggestion? The sex lives of insects.

The result was Green Porno; released in 2008, the first series was a roaring success, garnering four million hits on YouTube - with Rossellini writing, directing, producing and starring (acting out mating rituals in everything from the common housefly to the garden worm). Comprising comic skits - and a far cry from the films her father once made - it nevertheless fulfilled a childhood ambition. "I always wanted to do films on animals when I was a teenager," she says. "I grew up thinking I'd be David Attenborough's assistant or work for National Geographic."

She loved doing it but says of her online adventure, "There is no money it."

"Sometimes that plagued me. You feel like maybe you can only work if it makes some money. For sure, I wouldn't have been able to do them when I was 35. I had two children to raise and the mortgage to pay. But as you get older, and enter into another phase of your life, you say, 'Well, I don't make a lot of money but that's OK, I have a pension.'"

Last year she released another online series, Mammas - celebrating all things maternal in the animal world. Motherhood, of course, is something Rossellini knows a lot about. She has an adopted son, also Roberto Rossellini (now 20), and a daughter, Elettra, the product of her three-year marriage to former model-turned-Microsoft boffin Jon Wiedemann, which came to an end in 1986. Elettra, now 30, has taken up where her mother left off, modelling - ironically enough - for Lancome.

Either side of her marriage to Wiedemann, Rossellini had been seduced by two of Hollywood's most compelling directors. In 1979 she married Martin Scorsese, while he was shooting his epic boxing drama Raging Bull. She was 27 at the time and eight years earlier had arrived in New York from Europe, making the transition from modelling to acting in the interim. The pair appeared together in the 1980 film Il pap'occhio, but the marriage only lasted four years.

After her second marriage fell apart, she and David Lynch, her Blue Velvet director, became a couple. The role of Dorothy Vallens in Blue Velvet, the torch singer tortured by Dennis Hopper's sadistic pervert, was unforgettable for Rossellini; an instant classic. Calling it "an important relationship in my life", she and Lynch were engaged for four years - up to the time she appeared, briefly, in his 1990 movie, Wild At Heart.

So the story goes, it was Lynch's phobia of cooking smells that broke the two up. Yet it didn't stop her gravitating towards more maverick men; several years later, she had an affair with Gary Oldman on the set of Beethoven drama Immortal Beloved. It was arguably at the peak of her love-in with Hollywood - roles in Peter Weir's Fearless, Lawrence Kasdan's western Wyatt Earp and Robert Zemeckis's Death Becomes Her all came around this time.

Not that Hollywood ever mattered so much. "I come from a world, with my mum and dad, where entertainment was a sin word. It isn't about entertaining. It's about art. It's about emotion. It's about mystery. So I don't come from that tradition of entertainment." Still, being the daughter of a legendary Italian director and a lionised Swedish actor must've meant Rossellini grew up thinking baying crowds and popping flashbulbs were the norm.

Born in 1952, 34 minutes ahead of her twin sister Isotta (now a medieval history professor), Rossellini has clearly dwelled on the philosophical nature of growing up close to the limelight. She cites an interview she saw on CNN the day before we meet - a young comedian growing up in South Africa under apartheid.

"The journalist was asking about his exceptional upbringing, because he was in apartheid. He said, 'When you grow up, you think what you have is normal. As you grow old, you find out about the different ways of living life.'"

Rossellini arrived at a time when her parents were shrouded in scandal. Bergman left her dentist husband for Rossellini's father - who was also married at the time - and was consequently ostracised from Hollywood for the next decade. Ed Sullivan refused to have her on his talk show, while a US senator called her "a powerful influence for evil". By 1957, their marriage had ended, and they divorced amicably (with Rossellini going on to have four wives and seven children).

The young Isabella, along with Isotta and older brother Renzo, was stationed in a Rome hotel and then a flat run by a housekeeper dubbed "the children's apartment". For a time neither parent lived there but would visit what Rossellini calls the "strange kibbutz" they had established. The children would be looked after by their aunt, their grandmother, the housekeeper and a series of nannies and babysitters. "It suited me very well," Rossellini once said about this most bizarre of domestic arrangements.

"I wasn't born saying 'Oh, my parents were famous' or 'My parents are artists'. I thought that was normal," she reflects. "And as I grew older, I understood the majority of people might have had different lives. So you learn as an adult the differences. When I grew up, I had my mum and my dad, and then they went out because there was a film to make or they came back. Mamma especially - she was very famous and she had a hard time going out, because there were always people following her. But then you find out that is not the case for all mothers."

Bergman was frequently travelling the world, making movies, meaning that Rossellini saw far less of her than of her father. But when Rossellini was 13, she fell ill with scoliosis - requiring a major spinal operation that took 18 months to recover from. Bergman decided to take a step back from her work during this period to be with her bedridden daughter. "I was moved by her decision and felt guilty about taking her away from what she loved so much - acting," Rossellini wrote in her 1997 memoir.

You get the sense she was in awe of her mother - who had remained a somewhat distant figure. "When I was younger, I think it was difficult to imagine myself being an actress, because my mum was so famous. I was intimidated by the possibility of being compared to her. So when I concentrated more on modelling - and the great success I had in that - it gave me the answer I needed." Even then, spending time with her father on his film sets in Rome, she knew "I would remain in the realm of the film business".

She denies it was ever a pressure carrying the family name. "What kind of pressure do you imagine it gives me?" she retorts. "I don't know. I feel like I'm staying in my family business. Not only my parents, but my grandparents were in film. My grandparents from my father's side - [they] transformed all the stables of Rome into cinemas at the beginning of the century. And my mother's father was a photographer. So I feel like I'm third generation."

You imagine her father would be rather proud of the way her acting career evolved - working with such independent talents as James Gray (Two Lovers) and Peter Greenaway (The Tulse Luper Suitcases). Her latest indie venture sees her in Enemy, a brilliant, terrifying and surreal adaptation of the story by Jose Saramago. In it, Jake Gyllenhaal plays a restless university professor who one night spots his exact double in an old movie - and makes the foolhardy mistake of tracing him.

"I love the subtlety of the film," she says. "It reminded me of Kafka. It's very metaphysical, yet it's also a solid thriller. It made me leap up out of my seat at the end." Indeed, the ending - too juicy to reveal here - is good enough to rank alongside some of the great finales of all time. Rossellini, though, is in a "teeny" role. "I kept saying: 'Are you sure I'm staying? I hope I'm not edited out!'" There's little chance of that, with Rossellini's presence integral to the film's unsettling atmosphere. She plays Gyllenhaal's mother, and offers the first indication that everything is not what it seems in this story of doppelgangers. The film is directed by French-Canadian auteur Denis Villeneuve, who worked with Gyllenhaal on last year's kidnap drama Prisoners, though it could just as easily have come from the mind of David Lynch.

"My god, he's the most charming director ever," she says of Villeneuve. They first met at the Sundance Film Festival, but it was the film's producer Niv Fichman who offered Rossellini the role in Enemy. They'd worked on Guy Maddin's The Saddest Music In The World - another fine example of Rossellini's adventurous taste in films, playing a legless beer baroness - and remained friends. "Sometimes, when he comes to New York … we go to the opera together."

She may never have matched her mother's cinematic output but as Enemy shows, the roles have always remained interesting. And if film were to finish? "I have other alternatives. Studying is wonderful. And then I have the farm. If for whatever reason, films are to come to an end, because I can't find films or I'm not offered films, or can't find money to make my films, I would miss it. But I missed modelling and I survived it."

What did she miss about modelling, once the work began to evaporate? "I miss the talent, the people. Modelling is fun. You work for three or four days - whereas with films you go away for four months and generally get very homesick. It's a wonderful experience, but modelling moves very fast. So it was lighter. Especially when it came to family. You didn't have to leave them so much, after doing films."

For the moment, she doesn't have to think about alternatives. She recently completed Silent Life, a film about Rudolph Valentino. And, unlike many, she has no wishes to look back. "I'm not so nostalgic about youth," she says. "I love making my films. I feel very fulfilled, I feel happy." She beams a smile, momentarily. "I feel like a happy person." n

Enemy (15) opens on May 16. Isabella Rossellini's short film series - Green Porno and Mammas - are on YouTube.