Catherine Zeta Jones gives Michael Douglas a kiss for their joint birthdays

Happy birthday to the happy couple! Catherine Zeta Jones was in a festive mood as she celebrated her joint birthday with husband Michael Douglas by giving her longtime love a sweet kiss on the cheek on Sunday (Sept. 25).

The Welsh actress, who turned 47 at the weekend, is 25 years younger than Michael, who is now 72. But despite the age gap, it was clear from their sweet photograph that this couple’s romance is as healthy as ever.

"A birthday kiss for my hubby," she captioned the sweet photo which she shared via Instagram. "Happy Birthday to you and me."

Basic Instinct star Michael is grinning from ear-to-ear in the photograph, his eyes hidden beneath dark sunglasses. Catherine, also wearing sunglasses, is puckering up to plant her birthday kiss on his cheek.

COUPLES WITH BIG AGE GAPS

The happy pair have shared a few cute romantic moments with their fans this year. Back in March, they returned to the scene of their marriage proposal – Aspen, Colorado – and snuggled up together for a sweet photograph.

"16 years ago, this was the spot where my husband proposed," the Chicago star wrote alongside the romantic shot.

Sharing his own, similar, snaps, Michael added: "Scene of the crime... where I proposed to Catherine, New Year's Eve, 1999."

The Hollywood love affair is clearly very much back on track following their brief split back in 2013. Michael spoke about the secret of maintaining their long-term relationship while attending an awards event earlier this year.

"I think it's just moment to moment," the star told reporters. "Catherine reminds me, I like to say sometimes, we all make more effort with strangers than we do to the people closest to us."