Culkin presumably met Saget, 59, through 41-year-old Green, a longtime friend of the notoriously private former child star. Saget and Culkin both starred in Green's animated Adult Swim television series, Robot Chicken.
Saget also posed this cute selfie with Culkin and Green backstage at his Broadway show Hand to God, in which the Can't Hardly Wait actor gives him a giant bear hug.
"So fun my friend @SethGreen, his beautiful wife @ClareGrant, and Macaulay Culkin came to @HandToGodBway last night," the Full House star wrote.
Culkin running around New York City during the holidays is obviously giving us some much welcome Home Alone flashbacks. In October, ET exclusively caught up with a few of the stars from the 1990 classic to celebrate the beloved film's 25th anniversary. Director Chris Columbus recalled shooting the film's most iconic moment -- a then 9-year-old Culkin's signature scream.
"The script called for [Macaulay Culkin] to put shaving lotion on and suddenly it burns his skin and he screams," Columbus said. "We didn't know it was going to be the universal image for Home Alone."