Hollywood's finest flocked to Washington, D.C. for the annual White House Correspondents' Association dinner. Kristin Davis (in vintage Balmain), Cynthia Nixon (in Calvin Klein), Jimmy Fallon, Jessica Alba, Scarlett Johansson mingled with President and Mrs. Obama and other politicos and media bigwigs before a sit-down dinner in the Washington Hilton's Independence Ballroom. President Obama jokingly introduced Jay Leno, the night's key speaker, as "the only person whose rating fell more than mine this year." Then came the exclusive after-parties, where Justin Bieber rubbed elbows with Kim Kardashian and Gabourey Sidibe posed with Glee's Matthew Morrison. Click on the gallery to see all of the stars in Washington.