By James Mottram

Bill Nighy had a shock recently. The actor had laser eye surgery. "When I took the first bandages off, and went in the bathroom, it was a revelation!" he says, chuckling. "I mean, you kind of know how old you are, but I didn't really know how old I was!" He's sitting in an armchair in a suite in London's Soho Hotel, peering over a pair of black-rimmed glasses. "I didn't think, 'Oh my god, it's all over!' I just thought, 'Oh I see - you're one of those! You're one of those blokes who is old!'"

Nighy is being a little harsh on himself. He may have turned 65 in December but he still looks in fine fettle. As if to celebrate the fact GQ recently polled him at Number 29 in their list of Britain's 50 Best Dressed Men, he's sporting his trademark bespoke navy suit, pale blue shirt and silk tie. He's slim and trim (you suspect a little treadmill work) and has an enviable thicket of hair that's gradually trading light brown for silver. The only thing at fault is his right hand, which is clenched tight when we shake, due to an injury. "It doesn't hurt," he assures.

Certainly, retirement is not on the cards. If anything he's working harder than ever; the past dozen years have been remarkably fertile. After what he calls "an average progress" - radio, television, theatre - he's found fame in film, in everything from Love Actually to the Underworld series of vampire movies. "I think it's probably the right way around," he says, of his late-bloom. "I just wish I'd known when I was younger, because I would've arranged to be more cheerful! You think, 'I could've just relaxed!'"

Yet for all this needless fretting, Nighy has much to look back on. In the theatre, he's repeatedly worked on stage with some of Britain's most celebrated playwrights - Tom Stoppard, David Hare and, most impressively, Harold Pinter. "Not that I'm going to bore my grandchildren, but those are some of the things I'll tell them, if they stay still for ten seconds. I'll say I knew Harold Pinter. I did. I never thought I'd be anyone who'd met, sat down and discussed a play with Harold Pinter. It was a very important thing for me."

In person, Nighy doesn't look like his temperature ever gets above freezing; blame that distinct vocal pattern of his - a calming, charming, almost deadpan delivery. Yet he's perfect at expressing a sort of lived-in louche quality - like his fading musicians in both Still Crazy and Love Actually (where he delivered the infamous line, "Don't buy drugs, kids. Become a pop star and they give you them for free" - a choice nugget which he believes will be in his obituary).

Success has changed him, though. "I get very excited about the world and about people and things, I suppose, because I'm less anxious. I had an above-average tendency to undermine myself and, thankfully, I stopped believing my own shit. I think that's just time. It becomes embarrassing after a certain age to be - as it were - tortured. You're required to beat yourself up every day, and eventually you think, 'I don't believe you any more.'" He is happy...to a point. "I'm very much enjoying my life, generally speaking."

Age and the wisdom it can bring have come into the conversation for a very good reason. Nighy is promoting The Second Best Exotic Marigold Hotel, the sequel to the 2011 comedy-drama about an elderly group of travellers, co-starring dames Maggie Smith and Judi Dench. The first film, The Best Exotic Marigold Hotel, was a "weird hit", as Nighy puts it, making $136 million around the globe against a $10 million budget. That's a huge profit in anyone's accounting book, particularly given we're not talking A-List American stars.

One of the reasons Nighy enjoyed making the sequel was the chance to go back and "celebrate" the success of the first film with the "adorable" Indian crew. Then there was the opportunity to see Jaipur and Udaipur for a second time. "When you first go, it's quite a lot to take in. It's quite nice to go back at your leisure, when your senses have calmed down a bit and you can really appreciate it." Survival tips for India? "Smuggle Marmite and Yorkshire teabags in," he grins.

The original followed several over-65s as they left Britain for one last adventure, winding up in a homely hotel in India run by Dev Patel's genial host. There was romance and tenderness, and lots of people went to see it, which Nighy is at a loss to explain. "A bunch of old people going to India does not look like box office dynamite," he says. "There must be something where it unlocks a feeling of humanity. And possibly it reassures people about getting old." He stops to think. "Or maybe older people are just funny trying to be in love..."

In The Second Best Exotic Marigold Hotel, the film largely picks up where the original left off - though with Patel planning to expand his empire to two establishments. There are some new guests - including Richard Gere's writer and Tamsin Greig's singleton. But the real heart is provided by Nighy, as the mildly dithering divorcee Douglas, who is trying to pluck up the courage to make a play for Judi Dench's Evelyn.

"It can't have been easy," nods Nighy, given his character's journey some thought. "I think they've both been a bit beaten up by previous events. He has tried to love someone [his ex-wife, played by Penelope Wilton] in the face of great opposition for many, many years! Apart from anything else, he must've been undermined quite savagely over a very long period of time. So any idea of himself as desirable, attractive, eligible must've left the building some time ago."

Nighy, of course, has always played the reserved romantic rather well - think of his civil servant in the Richard Curtis-scripted The Girl in the Café for example. And there's something about him that seems to embody that. "I know it's a cliché, but I do find the struggle for certain kind of Englishmen to express anything very funny. It's what we're famous for. And I do find it amusing." Would he class himself the same way? "Oh, yeah! We're occasionally described as un-emotional. Nothing could be further from the truth. We're all burning inside."

Of course, for all his Englishness, Nighy has Scottish roots. His mother, Catherine, hailed from Glasgow. "My grandmother and grandfather were Irish and they'd come over looking for work, under a bit of a cloud I think with religious matters," he explains. "There were nine children - five brothers and four sisters. And they lived in what my mother called 'the Gorbals' and my mother came down south when she was 15, with two of the other girls and my grandmother and they worked as seamstresses." Later, they sent money back home to bring the rest of the family down.

The youngest of three, Nighy was born in Surrey, where his father Alfred, ran a garage. He never visited Scotland in his youth. "It would've been too much [for the family] to go up there." Yet he points out that his first professional job - "where I didn't have to paint the set or drive the van" - was at Edinburgh's Traverse Theatre, in Olwen Wymark's Speak Now. "It was a sensational place to be," he says. "That was the first time I was just an actor. It was a bit of a relief, but it was also that thing...oh god, now I really am useless! No I don't even paint the set! Now I have to act!"

Nighy had discovered acting when he was young - school plays and the like - but in his mid-teens fantasised about being a journalist. "I had a completely romantic idea. I was going to have a good hat. It would be raining. There'd be a beautiful woman. She'd probably be in trouble. I might be able to help. I'd have a notepad. I would write stunning sentences, beautiful, flawless unassailable sentences." He decided to head to Paris, and live the artist's life. "My joke is to write the great English short story! I didn't write a word, predictably."

Winding up begging for money with pigeon-French, he returned home, humbled. Giving up his literary dreams, he joined the Guildford School of Acting, then moved into theatre. "I never expected to do anything but the theatre. I never expected to be on television, certainly not in a film. Things were different then. It would never have occurred to you." But gradually things changed. He "robbed a bank" on Softly Softly, and that put him on television. Three years later, he made his first movie - a bit-part in the 1979 Joan Collins saga The Bitch, playing a flower-delivery boy. He was paid £150 for a day's work, and met Ms. Collins briefly. "It was bloody marvellous," he smiles.

Like most actors, Nighy has paid his dues. "I used to go to auditions without the tube fare. You'd literally try and borrow the tube fare! I was a mess, but the theory is, they [the casting directors] can always smell desperation and you won't get it. You sit out there, it's a room like this, you come in and these people say, 'Go ahead, do the thing.' And you do the thing." He still remembers the worst audition of his life. "I had to have a sword fight as if I was on a horse! I was in somebody's front room and I had to come in and do the lines and [pretend to] ride the horse!"

While he worked steadily through the Eighties, he often endured months of no work. "Most actors know what it's like to be skint," he shrugs. He also struggled with alcoholism. "I worked with him way back when he was drinking," recalls Kenneth Branagh, who first appeared with Nighy in the television play, Easter 2016 back in 1982. "I remember he was just so incredibly glamorous and rock'n'roll. And also had that wildness then. Always had that explosive, dangerous thing."

Nighy stopped drinking in 1992, with help from his then-partner, actress Diana Quick. A year earlier, he'd enjoyed a considerable breakthrough, starring in television drama The Men's Room, when he played a womanising academic, but it wasn't until 2003 when he became a household name. Five productions, including the supreme television drama State of Play and Richard Curtis' hit rom-com Love Actually, both of which won him BAFTAS, were all released. "That changed the way I go to work."

Since then, he's been a regular fixture in Hollywood, from playing a tentacle-faced Davy Jones in two Pirates of the Caribbean movies to acting opposite Tom Cruise (and Branagh) in Valkyrie. He admits there's a part of him that rather enjoys the pampering. "There was one period where I thought, 'I'll just live in hotels. Someone else will be paying. And they will lead me around through airports, and I'll just do that all the time.' Which is pretty much what I do, except that I have breaks! It's a very nice existence. It's a privileged situation."

It's a situation, for the last few years at least, that he's faced alone. After 27 years together, and one daughter, Mary, who followed her parents into the profession, he and Quick called time on their relationship in 2008. Since then, he's been single, living in Soho. "I'm very happy on my own," he says. And there's evidently a part of him that wanted to strip back his life to the bare essentials. Richard Curtis, his four-time collaborator, reports that he even ditched his vinyl collection and lives in "one of the most under-decorated venues in the world".

If you were to enter Nighy's house, you'd probably find a well-thumbed copy of Ford Madox Ford's Parade's End - his favourite novel. His film tastes range from the Bourne movies to Paul Thomas Anderson's Punch-Drunk Love and he "loves anything" with Gene Hackman or Denzel Washington. As for music, he digs James Brown. "I have on my phone his performance at the teenage music awards," he says, tapping at his chest, "when he was second on the bill to the then relatively unknown Rolling Stones and he wasn't happy about it." Somehow his love for the Godfather of Soul seems fitting.

Since completing his Indian sojourn for Marigold Hotel, Nighy has been treading on very hallowed British ground - the forthcoming big screen remake of Dad's Army. It's the sort of notion that might appal fans of the classic sitcom about the Home Guard in the fictional Walmington-On-Sea; certainly Nighy had his doubts. "I was more than a little nervous," he admits. "I was very, very nervous, and I resisted it at first." But then the cast started to assemble, from Toby Jones as Captain Mainwaring to Michael Gambon as the frail Godfrey. In another brilliant piece of casting, Nighy was asked to play Sgt. Wilson, originally played by John Le Mesurier.

"I'm never going to be John Le Mesurier," he says, before musing on just how "strange" it is to reboot a classic character. "It would hardly ever happen which you play a part that not only has been made famous but is beloved. But I would look at Toby Jones and think, 'We might just make it. We might just be OK.' He is brilliant as Captain Mainwaring. What's brilliant is, it's nothing to do with Arthur Lowe and everything to do with Arthur Lowe. It's perfectly pitched." He sighs. "Then again, people may not forgive us for not being them."

After a short break, Nighy will then head off to New York for the Broadway run of David Hare's Skylight, which he successfully did in London last year. Again, he will be on stage with Carey Mulligan and directed by Stephen Daldry. His last foray on Broadway was in Hare's The Vertical Hour with Julianne Moore and teaming up with him for this was divine. "It's one of the great plays in the English language," he says. "It's daunting and it's extremely gruelling doing it. But once you're up and running...it's wonderful to deliver such a play."

While Nighy's success in the autumn of his career runs entirely contrary to the way Hollywood tends to discard older actors, it gives hope to us all. "I am an optimist, in terms of human nature," he nods. "I don't think it's peculiar to me. The thing to dare to assume is that there's a benign future up ahead, rather than view it with a nameless dread - an assumption that things are probably going to go wrong. I've had my ups and downs but mostly I've been very fortunate." So no regrets? He shifts in his chair. "I'd like to have been cooler!"

The Second Best Exotic Marigold Hotel (Pg) opens on February 27.