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.😘."