Catherine Zeta-Jones gives 'unfortunate' admission about married life with Michael Douglas

Catherine Zeta-Jones has provided an 'unfortunate' admission about married life with husband Michael Douglas.

The acting pair met way back in 1998 at the Deauville Film Festival and instantly hit it off.

Zeta-Jones, 56, and Douglas, 81, got engaged in 1999, before saying 'I do' in November 2000.

As well as welcoming son Dylan, 25, and daughter Carys, 22, over the years, the celebrity couple also share the same September 25 birthday.

While the pair did separate in August 2013, they reconciled a year later - and their relationship certainly looks pretty strong from the outside.

And in a recent interview with Hello! magazine, Zeta-Jones detailed how her own self-confessed competitiveness runs in the family, which can have its drawbacks.

The celebrity couple have been married for almost 25 years (Dave Benett/Getty Images for Aston Martin)

When asked by the outlet if she has a competitive household, The Mask of Zorro star responded: "Yes I do. We all unfortunately… We all [do]. But it's a healthy one."

The pair have done countless interviews over the years discussing their relationship, including that breakup in 2013 and how they got back together.

"It can't be a one-way street," Douglas said on The Ellen DeGeneres Show in 2015. "But I'm crazy about her. And yeah, I think every couple has their difficult times. The only problem is, as you well know, we're all in the public eye, and it tends to get a little more exposed than most. We're back stronger than ever."

Last week, Zeta-Jones and Douglas marked their birthday, with Douglas taking to Instagram to share a sweet picture of them together.

Captioning the post, the Wall Street star said: "To my birthday sister—what a joy celebrating another year with you! Congratulations on your spectacular game at the Celebrity Ryder Cup. Happy Birthday to the love of my life @catherinezetajones.”

Catherine Zeta-Jones and Michael Douglas share the same birthday (Arnold Jerocki/Getty Images)

While many fans congratulated the pair on their birthdays, some picked up on the ‘birthday sister’ comment and argued it came across as ‘weird’ to them.

One user wrote: "Did you just call your wife sister or am I tripping?"

Another added: "That’s his wife, not his sister, what does he mean birthday sister."

Despite the bizarre comment, Zeta-Jones thanked her husband in the comments section without revealing any potential nicknames she has for him.

She wrote: "Happy birthday darling. I can't think of anyone else to share a birthday with."

Zeta-Jones' post to mark her husband's birthday was a little less peculiar, as she penned: "Happy birthday Michael! Sharing this special day with you is once in a lifetime!"