It seems fitting that Steven Soderbergh's proposed swansong, Behind The Candelabra, should be about Liberace.

The flamboyant pianist – played marvellously by Michael Douglas – was always the consummate showman. Arriving for our interview in casual beige and blacks, Soderbergh may be less colourful but he's no less the entertainer. He's made 26 films in 24 years, a remarkably prolific run that included a Best Director Oscar for drugs drama Traffic.

Now he's come full circle. We're sitting at the luxurious Hotel Du Cap, near Cannes, where it all began for Soderbergh when his 1989 debut Sex, Lies and Videotape won the Palme d'Or, turning him – for a time – into one of America's hottest directors. He's been to Cannes plenty of times since – The Limey, Ocean's Twelve and Che all played here – but there's something quite right about returning to the competition (even though the film is ultimately overlooked) with what may very well be his last film. "It's a nice symmetry," he nods.

Admittedly, it's hard to believe that the Louisiana-born director – who turned 50 in January – is planning to quit. The past 12 months he's been busier than ever, with the release of his pharmaceutical thriller Side Effects, espionage action tale Haywire and male stripper comedy Magic Mike, the most profitable film of his career. Is he really serious? "I don't think I'm historically known for not doing what I say I'm going to do. But there's obviously a lot of scepticism as to whether I will stop making movies forever."

So what has left him disillusioned with the business? "It's just less fun," he says. "There's always been a lot of fear but now there's a lot of fear." In the case of Behind The Candelabra, studios balked at the overtly gay content, with the story detailing Liberace's warts-and-all relationship with buff young man Scott Thorson (Matt Damon). Instead, he turned to television, gaining funding from HBO (meaning while the film hits cinemas here, in the US it will be shown on the cable channel).

Certainly the film may shock some for its frank portrayal of Liberace's sexual escapades with Thorson – not least with Damon and Douglas grinding away between the sheets. While Soderbergh claims that "there's nothing gratuitous about it", he admits when he got in the editing suite he was taken aback by the gusto of the sex scenes between his stars. "They weren't shy!" he laughs. "They just did a Thelma and Louise. They grabbed hands and just jumped off the cliff and never looked back. It was exciting to watch."

Yet despite the fabulous costumes and outlandish decor favoured by Liberace, as Soderbergh points out, his time with Thorson – aside from their 39-year-age gap – was not so out of the ordinary. "They deal with the same issues that everyone deals with in a long-term relationship, except it's amplified because of the environment, which is so extreme and so crazy. That's part of what I loved about it. They are having the conversations that other couples have, but they're sitting in a hot tub and drinking champagne. I loved that contrast."

Rendered with a warmth and humour that has often been lacking from some of Soderbergh's more clinical films, it also touches on the bizarre notion that fans of the phenomenally camp Liberace had no idea he was gay. "I just don't think they cared. In a weird sort of way, if he was trying to appear more masculine, then his homosexuality would've been a point, because there would've been some conflict between what he was and what he was trying to be. In this case, he seemed on stage to be completely who he was; you're just watching a guy whose very enthusiastic."

As for Soderbergh's enthusiasm, towards filmmaking at least, there can be no question that it has waned. After 1998's Out of Sight got him back in the game, following a period on the fringes after his Sex, Lies follow-ups flopped, he's craftily mixed box-office hits, like the Ocean's trilogy, with more experimental fare – notably Bubble, which was the first film to be released simultaneously in theatres, on cable and on DVD. Yet turning 50 has clearly made him think. "There's no question, I feel a little out of synch with movie audiences. Not completely. But I feel a little old."

Inevitably you feel he wants to spend more time with his wife of 10 years, writer and journalist Jules Asner, though Soderbergh could hardly be accused of slowing down. "I can't do nothing," he says. "I'm too restless. He's just launched his new website,, partly to sell logo T-shirts (including "Perennial Armored Car" from his film The Underneath) and a forthcoming range of limited edition headphones and partly to auction off memorabilia from his films. "My daughter [Sarah, from his first marriage to actress Betsy Brantley] doesn't want it," he shrugs.

An avid painter – he's currently taking lessons from renowned artist Walton Ford – more intriguingly, he's also looking to get into the liquor business. During the making of his bio about the Cuban revolutionary Che, his Bolivian casting director introduced him to the drink Singani.

After much behind-the-scenes work, he currently has 250 cases sitting in a warehouse in Florida. He's even planning to get Damon to do the commercial. "Putting me in charge of a hard liquor importing business is like having Clooney running a girls' dormitory," he smiles. "But hopefully I won't turn into Scarface."

Behind The Candelabra opens on June 7