The tricky, implausibly huge UK rockers alt-J are coming out with the new album Relaxer this summer, and they were musical guests on The Tonight Show last night. The trio had some help: With the Roots (or at least ?uestlove and the horn section) backing them up, they played “In Cold Blood,” the album percussive, idiosyncratic single. Watch the performance below.

Relaxer is out 6/2 on Canvasback.