The actress, 38, cozied up to the actor, 53, at Bionic Yarn, G-Star and Hennessy Privilege's party celebrating Pharrell Williams and his Oscar-nominated song "Happy" in L.A. Thursday. Theron looked stylish in an Alexander Wang top and Stella McCartney pants, while Penn wore head-to-toe black.
At one point in the evening, the Million Ways to Die in the West star adorably rested her head on her boyfriend's shoulder. In addition to chatting with Williams, Theron also caught up with daredevil Johnny Knoxville and jeweler Lorraine Schwartz. Theron and Penn's affectionate outing marked the second time that they've attended an official event since the Help Haiti Home Gala in L.A. on Jan. 11.
Earlier that night, Penn dined solo at L.A.'s Sunset Tower Hotel. When the couple left the premises holding hands, an eyewitness tells E! News, "They seemed happy and at peace."
The A-listers have become increasingly comfortable stepping out in public together now that their romance is public info. "They are spending night after night together and moving very fast," a source recently told E! News. "It seems like it's getting serious and that they can't get enough of each other."
Theron is scheduled to present at Sunday's Academy Awards—perhaps she'll bring Penn as her date?