Chad Kroeger is not a happy man. No, the Nickelback star, 37, took to Twitter to hit back at his fiancee Avril's Lavigne's ex-boyfriend Deryck Whibley after the Sum 41 man had weirdly dressed as his former love for a Halloween party, with current girlfriend Ari Cooper attending as Kroeger.

Still with us? Well, clearly unamused by the stunt, Kroeger took to Twitter to hit back, saying, "Hey Deryck loved the costumes! We were going to dress up as you guys this year but all the parties had celebrity themes haha!" Ouch. But a fair point. But then he's in Nickelback. Whibley, 32, and Lavigne, 28, split in 2009 after three years of marriage, with the latter going on to date Brody Jenner of 'The Hills' fame. Seemingly out of nowhere, the singer announced she was engaged to marry Kroeger in August though maintained she was still good friends with Whibley. She told Ryan Seacrest, "He's one of my best friends, and we work really well together and we stay in touch. I think we're very lucky. We've been friends for a really long time and we always will be family. We have a connection. Things are good. I'm really grateful for that."

Lavigne released her fourth studio album Goodbye Lullaby in March 2011.