Joined by girlfriend Eva Mendes, the Big Short star, 35, soaked in the night's success during the show's afterparty at Dos Caminos restaurant in New York City early Sunday morning. "They sat together all night," a party goer tells PEOPLE. "People kept coming up to talk to them. Eva had a whole group of friends with her."
The new parents, who welcomed daughter Esmeralda in September 2014, were soon joined by another proud dad. "Justin Timberlake came with a huge group of guys," says the onlooker. The singer was "very friendly with Ryan and they hung out for a while, chatting for a long time."
Could be Timberlake was picking his former fellow Mouseketeer's brain as he and wife Jessica Biel welcomed their own baby boy Silas this past April.
As if that wasn't enough male star power in the room, "Mike Myers was there, John Stamos stopped by and Jonah Hill hung out with Lorne Michaels all night," says the insider. "It was a crazy party!"