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

ROCK THE CRADLE

Ashlee Simpson-Wentz (alongside Entertainment Tonight Canada's Rick Campanelli) shows off a few rock-inspired baby onesies Saturday at the re-launch of the Request clothing line at Zellers, Square One, in Mississauga, Canada.

Check out Ashlee's maternity style here.