Inside Demi Lovato's 30th Birthday: Paris Hilton and Kristen Stewart Help Celebrate

Demi Lovato celebrated her milestone birthday with a star-studded party, including her pals Paris Hilton, Kristen Stewart, Ashley Benson and boyfriend Jute$. The ‘Substance’ singer was spotted blowing out candles to a custom cake. Of course, ET surprised Demi with a cake of our own earlier this month during her tour rehearsal.