'Marriage is hard work' - Actor Michael Douglas opens up on his brief split from his wife Catherine Zeta-Jones

Legendary American actor and producer, Michael Douglas has opened up on his brief separation from his wife, Catherine Zeta-Jones, insisting it was a mutual decision to split.

The couple, who met in 1998 and got married in 2000, went through a temporary separation in 2013.

At the time, the Welsh actress confirmed that the couple were 'taking some time apart to evaluate and work on their marriage.'

Douglas, who is 25 years Zeta-Jones's senior, has now spoken out about the split.

Speaking to The Sunday Times to promote his new memoir One Helluva Ride the 82-year-old was asked how he 'won back' his wife after their separation. A terse Douglas replied: 'What, I won her back? It was a mutual.'

He continued: 'You know, we had our problems but I love her dearly and, 25 years, you know.

'I mean, I don't know about your marital status, but marriage is a lot of work, you know. And so, you know, we're good. We're in good shape. It's all I can say.'

Writing about the brief break in the memoir, Douglas said: 'I never gave up hope that we would reconcile.' 

Their 2013 split came two years after Zeta-Jones revealed that she was battling depression and had been diagnosed with Bipolar II disorder, which she sought treatment for in a mental health facility that year.

Douglas was also battling cancer after receiving a diagnosis in 2010.

Zeta-Jones then returned to a mental health facility in 2013 to continue treatment for bipolar. 

Around the same time, Douglas claimed in a controversial 2013 interview with The Guardian that the type of cancer he had can be caused by oral sex.

'This particular cancer is caused by HPV [human papillomavirus], which actually comes about from cunnilingus,' he told the publication. 

He later publicly apologized in a 2015 interview with Event magazine. 

'It was one of those things… and I so regretted any embarrassment that it caused Catherine,' he said.

The couple share two children Dylan, 26, and daughter Carys, 23.