Watch Bob Weir, Trey Anastasio Cover Lady Gaga's 'Million Reasons'

Grateful Dead, Phish guitarists performed acoustic duo version of 'Joanne' ballad at Florida's Wanee Festival

Grateful Dead's Bob Weir and Phish's Trey Anastasio teamed for a live cover of Lady Gaga's "Million Reasons" at Florida's Wanee Festival.

The Grateful Dead's Bob Weir welcomed Phish's Trey Anastasio onstage for a five-song set during Florida festival Wanee. The duo performed material from their respective bands, alongside one surprising cover: Lady Gaga's "Million Reasons."

The guitarists played the song on acoustic guitars, alternating lead and harmony vocals. The arrangement was a bit shaky, as they fumbled repeatedly with the chord progression – even prompting a few chuckles from Anastasio throughout. But when they locked in, the jam band veterans drew out a satisfyingly earthier angle on Gaga's Joanne ballad.

Weir and Anastasio also performed Grateful Dead's "Deep Elem Blues," "Friend of the Devil" and "Bird Song," along with Phish's "Miss You."

The duo previously united, along with the other surviving members of the Grateful Dead (Phil Lesh, Bill Kreutzmann and Mickey Hart), during the 2015 Fare Thee Well concerts, a series of goodbye shows celebrating the band's 50th anniversary. As Relix reports, the guitarists also linked up during Phish's October show in Nashville, where Weir performed for the entire second set.

Last year, Weir released Blue Mountain, his first solo album since 2000's Evening Moods