Avril Lavigne's ex-husband dresses as her

Avril Lavigne's ex-husband went to a Halloween party dressed as her.

Deryck Whibley dressed as the 'Sk8r Boi' singer - who he was married to between 2006 and 2009 - for a Halloween party this weekend, while his girlfriend Ari Cooper went as her new fiance, Nickelback singer Chad Kroeger.

Related: Avril Lavigne to marry rocker

However, Chad appeared unimpressed with the imitation, tweeting: "Hey Deryck loved the costumes! we were going to dress up as you guys this year but all the parties had celebrity themes haha! -CK (sic)."

Deryck, 32, is the singer in rock band Sum 41, who were huge in 2002, but have had mixed fortunes of late.

Chad, 37, later sent another message to Deryck, confirming he was only joking, writing: "You owe us a couples bowling grudge match see you when I get back from Russia! -CK (sic)."

Although Deryck and Avril, 28, are divorced, they are still friends, and he worked on her 2011 album 'Goodbye Lullaby' as co-producer and guitarist.

Avril is likely to have found Chad's response amusing as she recently admitted she fell for the rocker because of his sense of humour.

She said: "He makes me laugh every day. He takes care of me in every way and is extremely attentive."