ABC News' Thea Trachtenberg reports:

Michael Douglas, a superstar known for macho roles in movies like "Fatal Attraction" and "Basic Instinct," is now playing one of the most flamboyant celebrities of all time.

It was 13 years ago, while working together on the movie "Traffic," when director Steven Soderbergh first approached Douglas about playing the role of Liberace. And a decade later, a script materialized and Matt Damon signed on to play his lover.

Although Douglas didn't learn how to play piano for this role, he, he studiously learned how to mimic Liberace's hand movements, and tested himself in many other facets of Liberace's life, such as wearing capes and rhinestones-and having love scenes with men-telling ABC's Elizabeth Vargas he had no trepidation about taking this role.

"As far as making out with Matt, it's not so bad," Douglas, 68, explained. "We rehearsed the scenes. For me, I guess that biggest thrill is when I first saw it, after a few minutes, I really forget it's Matt. Matt and Mike, you know? I just forget it's us."

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"He was really, in many ways, a tortured soul, Liberace," said Vargas. "I mean, nobody could ever know at that time that he was gay."

"I don't know if I'd say he was tortured. He protected himself," Douglas replied.

Douglas can identify more than most with the notion of trying to protect private struggles. His wife, Catherine Zeta-Jones, recently went back into treatment for her bipolar disorder.

"She is doing good. She is doing very well," Douglas said of his wife. "You know, bipolar issues, it involves meds. And if you don't balance it out right, it can take you on a slippery slope."

READ ALSO: Catherine Zeta-Jones Enters Treatment Facility

And his son, Cameron, who has had a very public battle with addiction, is now serving a nine-year prison sentence on drug charges, which Douglas feels might be a harsher punishment because of his famous last name.

"He received the longest sentence in the history of the American penal system for having drugs in prison," said Douglas. "And his case, it was a minor slip. So we're trying to understand it, how they justified it."

There was also Douglas' own painful battle with throat cancer three years ago, an illness that made this movie difficult for his famous father, Kirk, to watch.

"I think he was very uncomfortable with my death scene," Douglas said, thinking it might have hit a little close to home for him.

READ ALSO: Michael Douglas Talks Liberace, Cancer and Cameron

But in many ways, Douglas is enjoying second shots in life after beating cancer, and a second shot at fatherhood with two small children.

"When I had Cameron, I was younger, very much immersed in my career, so I never anticipating having children again, it's such a treat," Douglas explained. "Probably professionally and everything else, I'm eating it up a vengeance."

"Behind The Candelabra" premiers this Sunday, May 26, on HBO.