Justin Timberlake: From 'SexyBack' to 'Social Network' Set

Justin Timberlake suits up as he films a scene for The Social Network on Saturday (January 30) in Los Angeles.

The entertainer, who turns 29 TODAY, shot a scene with co-star Jesse Eisenberg, who wore a much more casual wardrobe – he was dressed in a bathrobe, pajama pants and slippers!

Last night, Justin caught a Timbaland concert with girlfriend Jessica Biel and her parents – and gave Timb a hand onstage!

“[W]hen JT strolled out, the place exploded,” MTV‘s Gil Kaufman reports. The old pals…slid into JT‘s ‘SexyBack’ and ‘My Love,’ which only served to remind the crowd just how much they adore the singer with the effortless vocals, fleet-footed finesse and serious beatboxing skills.” Sounds amazing!!

15+ pictures inside of Justin Timberlake filming The Social Network…