Sum 41 singer Deryck Whibley and his model girlfriend Ari Cooper wore Halloween costumes of his ex-wife Avril Lavigne and her new fiance, Nickelback frontman Chad Kroeger. In a fun and interesting twist, Deryck went as Avril and Ari dressed up as Chad. The Nickelback frontman addressed the story on Twitter, posting, "Hey Deryck loved the costumes! We were going to dress up as you guys this year but all the parties had celebrity themes."
