Former Motörhead guitarist Phil Campbell will sit in with Mass Mental, a side project led by Metallica bassist Robert Trujillo, when the band plays London on March 13.

Trujillo made the announcement of Campbell's participation on his Facebook page, describing himself as "so stoked" to add Campbell to his funk collective. The NME reports that Mass Mental's gig was originally scheduled for a smaller venue, but has been "upgraded" to the Electric Ballroom in North London. Also joining the band, which is led by Trujillo and Benji Webbe of Skindred, is a lineup that includes Paul Simon bassist Armand Sabal-Lecco, Ugly Kid Joe singer Whitfield Crane and Brant Bjork of Kyuss.

As previously reported, Campbell is also working on a solo album. According to some of his social media updates, it seems likely that the final product will include guest appearances from Judas Priest's Rob Halford and Slipknot drummer Chris Fehn. No release date has yet been announced for the project, but Campbell's taking his All Starr Band on the road later this year, with a Holland date in late April.

Campbell has also announced that he's working on a memoir of sorts that will focus on the "funny stuff" that happened during his tenure with Motörhead. "Some of it’s pretty bizarre and unbelievable," he said. "It’s totally funny, though. [It’s a book about] my experiences. It’s what would normally not happen if you weren’t in this band."

Motorhead Albums Ranked Worst to Best