Cee Lo Green left his soulful roots behind last night (June 14) and put on a rock front as he joined Mötley Crüe on stage for a special performance. 

The iconic heavy metal band played to a packed crowd at the Hollywood Bowl in Los Angeles yesterday and surprised fans when the singer walked out for an impromptu live collaboration. 

They rocked out with a mash up of 'Don't Go Away' and 'Forget You' and Cee Lo tweeted to bassist Nikki Sixx after the show to let him know he was grateful for the awesome opportunity:

"NIKKI thanks so much letting me rock with the crue!!!! A fan for life bro"

Sixx then replied with a message to his fans and included a photo from the night's great partnership:

"Nikki Sixx Mr @CeeLoGreen came onstage with us tonight at the Hollywood Bowl for a mash up of Don't Go Away-Forget You"

Watch the 'Crüe's performance of 'Girls Girls Girls' from last night's concert below: