im 100% certain (spoilers)

that i saw this on sky premier a few days ago cause i had tell me its ok lyrics stuck in my head and i just tried looking on youtube so i could listen to it and its not there.

to prove it the last part of the film adam sings this to molly i think and the other girl amy is looking at molly smiling but her face is shocked and she tries walking out. then amy tries to stop her and adam gets up and sings louder and molly stops a second and walks out (this is all going on while mollys date for the prom im guessing is stuck outside and cant get back in) and he ends the song and is stood on stage and is like wtf lol and he is still stood there for a minute and he turns around to see molly stood there and she walks over to him and they kiss.