A preview of Demi Lovato's Mortal Instruments track has hit the internet and we've got the details. So as we told you yesterday --- the track for the film is titled, 'Heart By Heart' but now we have actually heard a quick minute-long clip that has leaked on YouTube. As we assumed from the title, the song is definitely a slower ballad and is driven mostly by piano, but we can hear a bit of a rock sound too as Demi takes on an uber powerful chorus. Some of the lyrics go QUOTE 'When someone walks into your heart / Through an open door / When your hand finds the hand it was meant to hold. Don't let go' --- So we can only imagine that the song is inspired by the film's romance between the two main characters, Clary and Jace who are played by Lily Collins and Jamie Campbell Bower. Our favorite part of Heart By Heart though has to be leading into the chorus when Demi sings these lyrics: 'Know there are no one else's eyes that can see into me / No one else's thoughts can lift - Lift me up so high / Your love lifts me out of dark / And you know my heart by heart.' We are absolutely LOVING this new love song from Demi and can't wait to hear it on the soundtrack for The Mortal Instruments, but how are you guys feeling about the new track?.