Michael Douglas and Catherine Zeta-Jones have a combined age of 135, but they're still acting like a pair of newlyweds and crediting their insatiable sex drives as the key ingredient in their long-lasting love story.

Jones' $21.5m Central Park home with her husband Michael Douglas has grand gilded gold features - see rare photo

The first post was a throwback black-and-white picture of them from the beginning of their relationship (they met in 1998). “Happy Birthday to Michael and to me!!” the Chicago star wrote in the caption. “This was us on our birthday 25 years ago! I love you with all my heart ♥️.”

What do you get your famous husband for his 80th birthday? Well if you’re Catherine Zeta-Jones, apparently, you post a naked picture on Instagram. In a romantic twist, the Chicago icon and her husband Michael Douglas actually share a birthday (albeit with a 25-year gap).

The Chicago actress cut a casual figure in black tracksuit bottoms, a suede jacket and black trainers, sweeping her glossy raven hair into a messy low bun. As Catherine planted a kiss on her husband's cheek, Michael also pouted, wrapping his arm around his wife's waist.

Catherine Zeta Jones and Michael Douglas have been married since 2000, after the Hollywood icon was smitten watching the Welsh actress in the movie The Mask of Zorro

The U2 rocker and Wednesday actress sang the medley of "Happy Birthday" together, directing their message to the Douglas while also including "Catherine's" name. Bono held a small plate with a single cupcake, candle ablaze as they belted out the familiar tune.

Michael Douglas and Catherine Zeta-Jones have long been synonymous with Hollywood stardom, and now their daughter, Carys Zeta Douglas, is poised to continue their legacy. At just 21, Carys has already begun to make her mark in the entertainment industry while balancing her academic pursuits.