Avril Lavigne and ex-husband, Sum 41 frontman Deryck Whibley, have had a friendly relationship even after their divorce -- they worked together on a few of her albums -- so when Whibley donned a Lavigne costume for Halloween, fans weren't sure if it was an honor or a dig to the 'Girlfriend' singer. And apparently neither was her new fiance.

A photo circulated of Whibley, dressed as Lavigne in a blond, pink and green wig with heavy black eyeliner and a Hello Kitty hoodie, and his model girlfriend, Ari Cooper, as Nickelback frontman Chad Kroger in a black Jack Daniels shirt, blond curls and fake goatee. As PopCrushers know, Lavigne and Kroger came out of left field to announce their engagement in August.

The photo eventually made its way to Kroger, who basically owned Whibley and Cooper with a tweeted response, dissing Whibley's lack of longevity and Cooper's, well, complete irrelevance. It must have felt good for a member of one of the most reviled (yet somehow highest selling) bands today to slay anyone else. Check out Kroger's reply:

 

Still, it doesn't appear that there's any bad blood between the couples, because Kroger immediately followed that tweet with another, implying that they all hang out regularly. It's unclear whether it was an attempt to ease the blow he dealt to Deryck or to clarify for fans that there's no real beef between them at all:

 

Cooper isn't the only one doing her own Nickelback rendition. Lavigne will cover the band's breakout hit, 'How You Remind Me' for an upcoming anime flick. Because if there's one thing there isn't enough of in this world, it's ... Nickelback songs.

Watch Sum-41 Cover Nickelback's 'How You Remind Me'