"Hey guys, wanna feel old?" he tweeted on Wednesday. "I'm 40. You're welcome."
Macaulay Culkin played a precocious child in Home Alone
Culkin was 10 years old when his hit film "Home Alone" was released, and the public has never really stopped seeing him as his Kevin McCallister character.
He had some fun with that fact last year with a commercial for Google Assistant in which he reprised the role.