Macaulay Culkin cracked up fans with a hilarious post about his birthday on Twitter.
The star, who celebrated his birthday on August 26, wrote: "Hey guys, wanna feel old? I'm 40. You're welcome."
He followed up with a second tweet that said: "It's my gift to the world: I make people feel old. I'm no longer a kid, that's my job."
Some fans were shocked by Culkin's age, with many poking fun at the fact on social media.
Culkin, who became a household name thanks to Home Alone and Home Alone 2, recently opened up to Esquire about growing old.
"I got an ulcer or two I gotta deal with," he said. "I don't poop like I used to. My body's like, 'Oh, is this what the beginnings of dying feel like?'"
Culkin, who made a return to acting last year in a movie called Changeland, also told Esquire that people nowadays assume he is "crazy" or "damaged".
"Up until the last year or two, I haven't really put myself out there at all, so I can understand that," he said. "It's also like, OK everybody, stop acting so freaking shocked that I'm relatively well-adjusted.
"Look: I'm a pretty peerless person," he continued. "If I was an accountant, I could look left and right, and there's other accountants sitting next to me in the office. It's not like that. It's one of those things where, like, the cliche that we're all snowflakes? That we're all unique? Well, you know what? I actually am a snowflake."