Michael Douglas Calls Wife Catherine Zeta-Jones 'My Birthday Sister' as They Mark Their Shared Special Days

Douglas turned 80 and Zeta-Jones turned 55 on Wednesday, Sept. 25, with the longtime couple posting tributes to one another on social media

Happy birthday, Catherine Zeta-Jones and Michael Douglas!

The longtime couple celebrated their joint milestone on social media Wednesday, Sept. 25, sharing posts honoring one another as Douglas turned 80 and Zeta-Jones turned 55.

"Happy Birthday to Michael and to me!! This was us on our birthday 25 years ago!" the actress wrote alongside a black-and-white throwback pic of her husband planting a kiss on her cheek.

"I love you with all my heart ♥️, our friend @jeanpigozzi snapped us in New York!!" Zeta-Jones added.

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Related: Michael Douglas and Catherine Zeta-Jones' Relationship Timeline

Sharing a stunning shot of his wife, Douglas wrote in his caption, "To my birthday sister, I love you with all my heart! May your new year be the best! @catherinezetajones ❤️."

"🎉 Thank you sweetheart!!!🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉," Zeta-Jones wrote in a comment.

She also posted a black-and-white photo of herself modeling in a bathroom, wearing nothing but a pair of stilettos as she stood in front of a sink.

"In my birthday suit!" wrote the Oscar- and Tony-winning actress. "After over 25 years of sharing my birthday day with my husband, I am running out of gift ideas! This is gift option two, golf balls being option one … of course 🤣."

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Related: Catherine Zeta-Jones, 54, Shows Off Her Curves in a Sexy Cutout One-Piece: ‘Caught Me Posing!’ 

The couple — who will celebrate 25 years of marriage next year and share two children — are regularly lovey on social media, and occasionally give insights into their strong (and fun) bond.

During a July appearance on The View, Douglas answered a question about what his wife makes him do when he loses a game of golf to her.

“Whip it out. Drop the trou and whip it out," quipped the Fatal Attraction star.

Douglas also noted during his interview that Zeta-Jones has gone a little easier on him as he’s gotten older, though.

“I’m going to be 80 now in September, so now I play off of ladies' tees, too. So I don’t have to do that anymore,” he said.

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