Two years ago, Mumford & Sons were forced to cancel their headlining set at Bonnaroo at the last minute due to bassist Ted Dwane’s emergency brain surgery. So when they returned to finally perform at Bonnaroo last night, they seemed determined to make it count. At the end of their set, Marcus Mumford brought out members of My Morning Jacket and Dawes, Hozier, and Jon Natchez — the sax player from the War On Drugs — for a cover of the Beatles classic “With A Little Help From My Friends.” Actor/comedian Ed Helms joined in on banjo, and photographer Danny Clinch played harmonica. Watch some fan-shot video of the performance below, which shows Mumford trading off lead vocals with Hozier and New Basement Tapes bandmates Jim James of MMJ and Taylor Goldsmith of Dawes.