Rocker Chad Kroeger has taken aim at his fiancee Avril Lavigne's ex-husband Deryck Whibley after the Sum 41 star and his model girlfriend mocked the newly-engaged pair by dressing up as them for a Halloween party.

Whibley donned drag and wore a blonde wig with coloured streaks and heavy eye make-up to attend the Saturday night (27Oct12) bash as Lavigne, while his girlfriend, Ari Cooper, showed off a long, curly hairpiece and a fake beard to mimic the Nickelback frontman's look.

The stunt didn't go unnoticed by Kroeger and he took to his blog on Sunday (28Oct12) to take a jab at Whibley.

He wrote, "Hey Deryck loved the costumes! we were going to dress up as you guys this year but all the parties had celebrity themes haha!"

Lavigne split from Whibley in 2009 and she became engaged to Kroeger earlier this year (12) after a whirlwind romance.