The Danish skinbeater teamed up with the British duo for a rendition of their finale song, Out of the Black, during their set at a San Francisco venue called Slim’s.
Fan-filmed footage of the intergenerational rock and roll collab has since surfaced (below), which shows RB drummer Ben Thatcher crowd-surfing on top of a wild, cheering throng while Ulrich hammers the kit with more gusto than should be legal for a man of his age.
Apparently, Metallica have been big Royal Blood fans for a while now, with frontman Mike Kerr telling Hot Press that they first rubbed shoulders with Ulrich last December, when he came to check out one of their gigs (and then, for some reason, took them to visit the house from the movie Mrs. Doubtfire).
“Lars Ulrich was a real surprise,” Kerr said. “I mean, he has two legs and two arms; he’s a regular guy. And really good company.”
Royal Blood are set to visit Australia this July for an exclusive live performance at Splendour In The Grass 2015.
Watch: Royal Blood – Out Of The Black (Live w/ Lars Ulrich)