Whibley attended the event with his partner Ari Cooper, who was dressed as Kroeger.
"Hey Deryck loved the costumes!" wrote the Nickelback frontman on Twitter.
"We were going to dress up as you guys this year but all the parties had celebrity themes haha! -CK."
Kroeger and Lavigne recently announced their engagement.
Whibley and the Canadian 'Complicated' singer were married for three years before separating in 2009.
Kroeger has said that he doesn't care about what people say regarding his plans to marry Lavigne, who is ten years his junior.