Kristen Stewart, Leighton Meester, Cynthia Nixon, Elle Fanning
Credit: Startraksphoto; Sipa; FilmMagic (2)

It's a big day for Hollywood birthdays! Kristen Stewart celebrates her 22nd today, Leighton Meester turns 26, Elle Fanning blows out 14 candles, and Cynthia Nixon rings in her 46th. Congratulations to these Aries ladies!

Plus, celebrate Kristen Stewart's birthday by clicking through her transformation!