With her pooch in tow, the Gossip Girl star celebrates her 21st b-day on the New York City set of her show. Plus: Ashlee Simpson, Lindsay Lohan, Paris Hilton and more

PICTURE IT!

Funnymen Will Ferrell and John C. Reilly stay in the picture (frame) during a photo call for their comedy Step Brothers on Friday in Berlin. The movie, already a hit in the U.S., opens in Germany on Sept. 11.