A Gossip Girl's Gotta Have a Dog!From Blake Lively to Leighton Meester, these Upper East Side gals (and guys) can't live without their must-have accessory: a pooch!

GUEST STAR

Spotted: Blake Lively's Maltipoo Penny – a regular guest on the Gossip Girl set – getting some warmth on a blustery day in New York City.