Looks like Leighton Meester's just joined a new Entourage!

The Gossip Girl hottie - she plays Blair on the hit show - was in La La Land yesterday to shoot an episode of Entourage with star Adrian Grenier at Urth Caffe.

You might recall Leighton playing virginal pop-singer Justine Chapin, who went out on a date with Vincent Chase in the show's first season.

Can't wait to see her big return now that she's all grown up!