Did Avril Lavigne sing back-up for Kelly Clarkson's song "Judas"?

Did Avril Lavigne sing back-up for Kelly Clarkson's song "Judas"? It sounds like it!!! What do you think?
Did Avril Lavigne sing back-up for Kelly Clarkson's song "Judas"?
Kelly did all the backup vocals for all the tracks on her new album. It's probably in the booklet somewhere... but I know I've heard her in interviews that she did all her backup vocals.
Reply:no...she would have been credited in the liner notes.