The pop superstar walked the red carpet at the AMAs in Los Angeles on Sunday (22Nov15) wearing a patterned top emblazoned with the iconic band's logo, prompting an outpouring of criticism from Nirvana fans.

Devotees flooded social media with taunts aimed at Justin, who was born just four weeks before Kurt Cobain's death in 1994, but the rock legend's widow Courtney has now spoken out in his defence.

The Hole rocker sent a message to the pop star via Twitter.com to lend her support, writing, "You're cool in my book @justinbieber xc (sic)."