If you're talking to Michael Douglas about playing Liberace the wrong place to meet would be a tattered bus shelter on the outskirts of a sink estate. You need somewhere with a bit of glamour.

We could not have hoped for better than the Hôtel du Cap in Antibes on the French Riviera. Some distance from Cannes, where Steven Soderbergh's Behind the Candelabra is playing in competition, the sprawling luxury location was the model for the Hôtel des Étrangers in F Scott Fitzgerald's Tender is the Night. A Travel Tavern it is not.

Mr Douglas joins your hard-working correspondent in a sort of luxury tent that opens onto an impossibly picturesque view of the bay. Yachts the size of frigates (literally, for all I know) jostle for space in a sea the colour of lapis lazuli.

Douglas looks every one of his 69 years. Recently recovered from throat cancer, he sports deep wrinkles set in worried skin that emphasises the absurd whiteness of his immaculate Chiclet teeth.

But he seems in very good form. Behind the Candelabra, which details the relationship between the flamboyant pianist and a naive tearaway named Scott Thorson, has just screened to ecstatic reviews. Both he and Matt Damon, who plays Thorson, have been singled out for particular praise.

“I guess I was nervous because he was a big guy, a Polack,” Douglas says. “He was barrel-chested. One thigh was the size of both of mine. His hands were huge. I’m not an impersonator. How do you capture all that?”

Very effectively as it happens. Made for the HBO television network, the film follows Thorson as he meets Liberace and, after another young man is ejected, becomes installed as chauffeur, live-in lover, secretary and surgically enhanced offspring. There is humour here. But it’s a disturbing film. Douglas’s jealous, manipulative showman employs plastic surgeons to remake Scott in his image. Further obsessive behaviour follows.

You will not need to be told that Michael is the son of the apparently indestructible Kirk Douglas. His dad and Liberace – both supernovae in the post-war years – inevitably rubbed up against one another. Did Michael ever meet Lee (as the pianist was known to pals)?

“I met him once en passant in Palm Springs at a corner,” he says. “My father was in his car and a guy came past in a Rolls Royce. I remember it was a convertible with the top down. The light was bouncing off his skin and his hair was perfect. Now I know it was a wig.”

This was, he thinks, about 1956.

“The nice thing about this part is that I am playing a nice guy. I don’t get to play nice guys that often. He was so generous. He was such a nice fellow.”

Now, hold on a moment. Earlier in the day, I bumped into Jerry Weintraub, producer of the film. He also spun the line that Behind the Candelabra deals with a nice guy who sometimes behaved a tad disgracefully. But the film strikes me as being unremittingly merciless in its treatment of Liberace. He moulds Scott into a plaything, then discards him without any apparent remorse. The Liberace seen in Candelabra is something of a monster.

“Well, he was when things turned,” Douglas says. “He did not like uncomfortable situations. When Scott became a drug addict, it was distasteful. He did give him a fortune in jewellery. But he reneged on the house he bought Scott. He was litigious. But we know enough guys who like young blonde bimbo girls. They know what they are getting into. They also get gifts and so on. But there’s always a payoff.”

Douglas knows about the ups and downs of the business. The son of Kirk's first wife, Dina Dill (also still with us), he grew up shouldering a terrifying weight of expectation. But he was also primed for the many disappointments that darken life in show business. Happily, there have not been too many of those. As long ago as 1975, he won an Oscar as producer of One Flew over the Cuckoo's Nest. A long running part in the TV series The Streets of San Francisco led on to big-league movie stardom in the 1980s and 1990s with such hits as Wall Street, Fatal Attraction and Basic Instinct. Nobody is better at playing untrustworthy creeps.

“That’s the biggest advantage of being second-generation,” he says. “My father was a movie star. So I do think of it as a business. There are wonderful benefits. There is none of that looking at the business through a quartz glass. I don’t know anything else. The thing that’s changed most is probably the digital press: electronic cameras, phones and so on. There’s a lack of privacy.”

Indeed, Michael and his wife, Catherine Zeta Jones, had to take action against a stalker some years ago. He has, in fact, passed through all of the key crises that assail the average movie star. In 1980, he had to withdraw from acting after a serious skiing accident. A decade later, he underwent rehabilitation for alcoholism and drug addiction. In Behind the Candelabra, Michael gets to deliver one of Liberace's great trademark quips: "Too much of a good thing is . . . wonderful!"

That can hardly be Douglas’s own catchphrase today.

“It might have at one time. But certainly not any more,” he says. “Because you get a little older and a little more conservative. You don’t necessarily push yourself to the boundaries as you might have when you were younger.”

The cancer experience must also have influenced his decision to slow down.

“You emerge a different person,” he says. “The illness itself is one thing. You have to monitor your alcohol. You choose not to be around smoke. That helped with the joy in performing that Lee had. For me the joy came out of being cancer free, from being able to work again. I’m so grateful this gift had been handed to me. It’s one of the best parts I have ever had.”

At an earlier press conference, Douglas broke down when discussing his pleasure at bouncing back with Behind the Candelabra. The team was ready to make the film when he was diagnosed and (Hollywood does occasionally deal in loyalty) decided to shelve the project until he recovered. Looking at the result, one can understand why Douglas was so keen to persevere. Yet there was a time when every A-list actor would run a mile from playing a gay role.

“As actors, we earn the right to do whatever we do,” he says. “I don’t owe anybody anything. I am sure Matt feels the same way. He’s a lot braver than I am. He’s in he prime of his career.”

Now this is an interesting comment. Can it still be the case that playing a gay role puts actors in a "dangerous" position? Well, it has been reported in many places that all the major movie studios turned down Behind the Candelabra because it was "too gay". HBO eventually took up the film for cable TV, but it will not go on theatrical release in the United States. (One hopes its appearance at Cannes and subsequent cinematic unveiling in Europe will cause those sceptical studio heads some embarrassment.)

I wonder whether Douglas would have accepted such a role 20 years ago.

“No, not in the prime of my career,” he says, with admirable frankness. “I wouldn’t have taken this role. I would have been scared in terms of where everything was at in the gay situation 20 years ago. We’ve come a long way. I don’t know. Matt is in the prime of his career and he didn’t even think about it. But there are not a lot of guys who, in Matt’s position, wouldn’t blink when offered that part even now.”

But why, exactly? Is the industry still so blinkered that playing a gay role could rule you out of future romantic leads? It seems absurd.

“It’s an identity that you might still be nervous about,” Douglas shrugs.

The role also presented more than a few technical difficulties. Liberace may have produced the cheesiest music imaginable, but there is little doubt that he knew his way around a keyboard. In the opening sections we see Michael zip through a boogie woogie with astonishing dexterity. It looks as if he’s now a bit of a maestro himself.

“I am not an accomplished piano player,” he laughs. “Steven originally gave me a piano teacher. But I said: ‘Promise me you can use a piece that we have Lee playing on film, so that I can copy it.’ So, I spent hours getting that right. I reckoned if the hands were in the right place only a few people would realise that I wasn’t doing it.”

Though he still looks a little delicate, Douglas seems to regard Behind the Candelabra as his first step on a new journey through life. There have been a few of those. It rather takes one aback to note that he has now been married to Zeta Jones for well over a decade. They have two children.

“I drifted away from acting. I have been married for 13 years, but I still consider myself in a new marriage,” he says, rather quaintly. “I never anticipated starting a new family and I have really enjoyed raising my kids. My priorities are completely different.”

One can’t help but return to that bout with cancer. Such an ordeal must colour every subsequent experience.

“I lost several people I know recently. Larry Hagman died recently from the same cancer,” he says, glancing at the vast carpet of blue behind my shoulder.

“Yeah, yeah. You smell the roses a bit more.”