Demi Lovato: 'Heart Attack' - LISTEN NOW!

Demi Lovato‘s brand new single “Heart Attack” has officially premiered online!

The 20-year-old singer was originally set to premiere the song on March 4th, but joined forces with Ryan Seacrest to surprise fans and post it tonight!

PHOTOS: Check out the latest pics of Demi Lovato

“Surprise! We’re premiering @ddlovato‘s new song “#HeartAttack” TONIGHT!! Go listen now,” Ryan wrote on his Twitter account, linking to the On Air with Ryan Seacrest site.

Unfortunately, On Air‘s site crashed almost immediately from all of the Lovatics trying to listen!

WHAT DO YOU THINK of Demi’s new single??