Michael Douglas says that the decision to stop taking her medication was the reason his wife Catherine Zeta-Jones returned to a treatment facility, but claimed that she is now on the road to recovery, according to Metro.

The 68-year-old actor admitted that the Welsh actress's mental health condition is often unpredictable.

"It's a slippery slope, this bipolar stuff," the Behind the Candelabra star said.

Zeta-Jones voluntarily checked herself into a residential rehabilitation clinic in May and returned home before Douglas left on a promotional tour for his new film. She was last in a similar facility for the disorder for five days in 2011 to take time to manager the disorder and adjust her medication.

Douglas was at the 66th annual Cannes Film Festival last month promoting Candelabra and said while there that his wife was doing well.

Douglas plays Liberace in the film, based on the autobiographical novel by Scott Thorson, which recounts the tumultuous 6-year relationship between the entertainer and his lover, a much-younger Thorson.

The Steven Soderbergh-directed the film also stars Matt Damon as Thorson, Scott Bakula, Dan Aykroyd and Debbie Reynolds.

Douglas did an impersonation of Liberace on the set of Traffic, his first film with Soderbergh in 2000.

The actor said he met Liberace once.

"He was a very great entertainer, a very generous person. When he'd play his piano, you were just captivated by the fact of how he loved what he was doing," said Douglas.

The film tells the story of the relationship between Liberace and Thorson and Liberace's fear of being exposed to the public as gay, as well as his quick decline after developing AIDS.

Douglas, who had not acted in a project in three years, also co-stars in the film Last Vegas, which he already shot.