Gossip Girl, Blake Lively, Leighton Meester
Credit: Courtesy of The CW

Gossip Girl fans, brace yourselves—the show's 100th episode airs tonight! Our favorite Upper East Siders have come a long way since this season one photo above, from Chuck Bass ditching his bow ties and pastel suits for a more streamlined look to Serena van der Woodsen's va-va-voom makeover. Tonight, it all culminates in Blair's royal wedding and Serena's Marilyn Monroe moment. Tune in at 8/7c to see the episode, and tell us: What do you think of the cast's fashion transformation?

Plus, browse our top 15 Gossip Girl fashion moments in the gallery!