It all starts with the wig, Matt Damon says. He was conscious that he was 20 years older than Scott Thorson, the young man with fluffy blond hair whose long affair with '60s showman Liberace is the subject of Behind the Candelabra.
Director Steven Soderbergh thought they could disguise the age difference with CGI. ''But he said, 'We didn't have to do anything, man, that wig is unbelievable!''' Damon laughs. Of course, the outfits studded in rhinestones helped, too.
Most of the talk about Behind the Candelabra has focused on Michael Douglas' towering performance as the exuberantly camp Liberace, whose twinkle-fingered virtuosity on the piano was matched by his glittering outfits.
What Damon brings to the film, however, is nuanced empathy as the perpetually junior partner in a dependent relationship. Even if he's merely suffering in silence, you find yourself watching him and suffering, too.
This is the seventh film Damon has made with Soderbergh. That it involved some torrid gay sex scenes never troubled him. ''It was like a no-brainer, such an easy job to say yes to. All these people are our friends.'' Anyway, he can't think of anything offhand that he would refuse to do for the right project.
''I'm sure there is. I wouldn't do anything that conflicted with my beliefs about the world. But f---ing Michael Douglas: that certainly wasn't it.''
His fear, given the wig and the bling, was that he could come across as a camp caricature. His solution was to enlist Gus van Sant, who directed Good Will Hunting and is gay himself, to watch his footage while they were shooting.
''I was like, 'Can you check my work? Just make sure that I'm good here!''' Damon says. ''So Gus would look periodically and say, 'No, don't worry, you're in the pocket.'''
Thorson wrote an autobiography about his five years with Liberace, also titled Behind the Candelabra. Damon kept a copy of the book on him at all times, but he never sought out Thorson himself: ''Steven didn't want me to meet him and I saw his point. I didn't think I'd get anything from talking to the guy 30 years later.''
What struck him was that, bizarre as Liberace was, the story was universal. ''I could see failed relationships I'd had echo in that relationship,'' he says.
''I'd been both people in different relationships over the course of my life. You know, just without the rhinestones.''
Behind the Candelabra will screen at the New Zealand International Film Festival.
- Sydney Morning Herald