Catherine Zeta-Jones and Michael Douglas
Rob Rich/Splash News Online
05/20/2013 at 09:00 PM EDT
Michael Douglas is hard at work in Cannes to promote his HBO film, Behind the Candelabra
, but he is ready to be back home with his wife, Catherine-Zeta-Jones
, who just completed her ongoing treatment for Bipolar II disorder
"She comes home tomorrow," he told PEOPLE on Monday. "She's doing a really good job of getting balanced. I'm proud of her."
The actress, 43, entered treatment for the second time
in April as Douglas, 68, was beginning to generate praise for his role as the flamboyant piano player and vocalist, Liberace.
Zeta-Jones, for one, is already a fan. "She loves it," says Douglas. "It cracks her up. She thinks it's a great movie."
Costarring Matt Damon
as Liberace's lover
, the film lent Douglas a new perspective on the legendary performer's lifestyle.
"He was a very hard-working guy who never seemed to lose his cool," he says. "It was a joy playing a nice guy. I don't get to play a lot of nice guys."
Look for much more from PEOPLE's interview with Michael Douglas in an upcoming issue of the magazine