Cassadee Pope To Perform With Avril Lavigne On The Voice

NBC have announced that Cassadee Pope will perform a duet with Avril Lavigne on the Season 3 finale of The Voice tomorrow night (December 18th).

Cassadee has already covered Lavigne's "I'm With You" and "My Happy Ending" on this season of The Voice. Any guesses on which track the duo will perform tomorrow?