The 35-year-old former child actor spent time with the 59-year-old Full House star and 41-year-old Robot Chicken creator after Saget's performance in the Broadway play Hand to God.
"Fun times last night after show in the #TimesSquare with friends @ClareGrant, Macaulay Culkin, and the master of the selfie, my pal @SethGreen," Saget captioned one of the photos on Instagram.
"Saw my buddy @bobsaget in the outrageous @handtogodbway last night - excellent cast, provocative show - really worth checking out," Green added on his own account. The actor's wife, voice actress Clare Grant, was also present for the mischief.
Culkin is known for the Home Alone movies, and voiced characters for Green on Robot Chicken from 2005 to 2010. The actor has stayed out of the spotlight in the past decade, but previously told 20/20 he doesn't regret his early fame.
"I wouldn't trade any of my experiences for anything in the world," he told Barbara Walters. "I'm very happy with who I am, and where I've ended up and I wouldn't change one thing. Because if you change one thing in the past, everything else is different."
Culkin had a multi-episode arc on TV Land sitcom The Jim Gaffigan Show this year, and will next appear in Adam Green's Aladdin with Zoe Kravitz. He also continues to perform with his comedy rock band The Pizza Underground.