The intimate party kicked off around 9:30 p.m. in a private area at Lucky Strike in L.A. on Saturday, Feb. 9, a source tells Us Weekly. Spring Breakers actress Ashley Benson and Arnold Schwarzenegger's son Patrick were in attendance. The group of young A-listers and enjoyed bowling while listening to music, and snacking on pizza, sliders and chips and guacamole.
Wearing a backwards cap, ripped T-shirt, leggings and Converse sneakers, Stewart, 22, showed up late to the event -- a little after midnight -- with a small group of friends, "She was being fun and social, bowling and high-fiving," the source tells Us. "She and Taylor definitely seemed to be good friends and she was living it up."
Was the birthday boy living it up as well? Not as much. The celebration occurred just shy of his actual 21st birthday, and a source tells Us he "drank nothing."
"Taylor was super nice, very polite," the insider says of the actor. Stewart's boyfriend and Lautner's fellow Twilight costar, Robert Pattinson, was MIA at the party, but the source tells Us that Stewart was being "really sweet" during the night.
"Everyone was having a blast," the source says. "Everyone was super into the bowling" and Lautner "is really good."
The party wrapped around around 1:30 a.m., but not before guests sang Lautner "Happy Birthday."
This article originally appeared on Usmagazine.com: Taylor Lautner Celebrates 21st Birthday With Kristen Stewart