Catherine Zeta-Jones Celebrates Her & Michael Douglas' Birthday With Sweet Video

Catherine Zeta Jones and Michael Douglas
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The couple share the same birthday.

It's a special day for Catherine Zeta-Jones and Michael Douglas!

The couple, who have been married for almost 18 years, share the same birthday: Sept. 25. On Tuesday, the actress -- who turned 49 -- took to Instagram to share a black-and-white video dedicated to her "president" on his 74th birthday. The clip begins with a scene from Douglas' movie, The American President. It then shows Marilyn Monroe singing "Happy Birthday" as photos of Douglas and Zeta-Jones flash on the screen.

"Happy Birthday to my very own President! My husband Michael," Zeta-Jones wrote. "I guess that makes me First Lady! Stranger things have happened! Go figure?oops, it’s my birthday today too.?."

The lovebirds have been celebrating their birthdays together since they started dating, something that Zeta-Jones told ET earlier this month that she didn't mind -- at first.

"It was a lot of fun [celebrating our birthdays together] when we were dating," she said at the Michael Kors New York Fashion Week show. "But now, it's like, 'OK, I want my own day.'"

At the event, Zeta-Jones was accompanied by her 15-year-old daughter, Carys. The mother-daughter duo made a stylish splash as they sat front row.

"I love this!" Carys marveled. "It's a dream to come back again."

See more of ET's interview with the two in the video below.        

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