Blake Lively as Marilyn Monroe and Leighton Meester as Audrey Hepburn on Gossip Girl Pictures

Spoiler alert: Blair is getting married on Gossip Girl's 100th episode, so it only makes sense that she would have one of her classic Audrey Hepburn dream sequences on her big day. This time, Serena's in the mix as Marilyn Monroe, and we have the pictures to prove it! Check out the photos to see Serena as the blonde bombshell, along with Blair as Breakfast at Tiffany's-era Audrey, and the boys decked out in tuxedos to reenact Gentlemen Prefer Blondes.

Photos courtesy of The CW