Catherine Zeta-Jones stripped down to her birthday suit in honor of husband Michael Douglas turning 80.

The 55-year-old showed off her gift idea in an Instagram post.

Zeta-Jones posed fully nude in the throwback photo. The actress stared into a mirror wearing only black heels with her hair pulled back.

"In my birthday suit! After over 25 years of sharing my birthday day with my husband, I am running out of gift ideas!" Zeta-Jones captioned an Instagram post. "This is gift option two, golf balls being option one … of course."

MICHAEL DOUGLAS, CATHERINE ZETA-JONES ‘SEDUCE’ ADULT CHILDREN WITH EXTRAVAGANT VACATIONS

Zeta-Jones and Douglas share a birthday – September 25.

"Happy Birthday to Michael and to me!!" she captioned an additional Instagram post. "This was us on our birthday 25 years ago! I love you with all my heart."

For his part, Douglas shared a photo of the "Chicago" actress with his own tribute.

"To my birthday sister, I love you with all my heart!" he wrote in the caption. "May your new year be the best!"

LIKE WHAT YOU’RE READING? CLICK HERE FOR MORE ENTERTAINMENT NEWS

Zeta-Jones and Douglas tied the knot in 2000.

The actress revealed the secret to their successful marriage is their strong connection in a 2021 interview with WSJ Magazine.

"My husband is 25 years older than me; that’s not a secret," the actress said. "With any relationship, it wouldn’t be normal if there weren’t any ups and downs. The constant is love is respect. We’ve never, ever lost our sense of humor, and we enjoy each other’s company."

"My husband and I spend a lot of time together because, unlike so many couples, we've never had a 9-to-5 job where it's consistent," she told the outlet. "We're either on or we're off. I'm really working 16 hours a day or I'm not. He's doing the same or not. So we've had in our relationship huge amounts of time where we've been just us."

CLICK HERE TO SIGN UP FOR THE ENTERTAINMENT NEWSLETTER

Douglas and Zeta-Jones share two children together: Dylan and Carys. The two are now adults, and Douglas noted it's a "treat" when they are around.

"Especially when you’re not forcing them," he said during an appearance on the "Today" show in April. "[I] said, ‘Catherine, look, they actually want to hang out with us.’ I said, ‘You know, it’s good.'"

"But we’ve got good trips," the actor noted. "We seduce them with good places to go."