John Mayer made a surprise appearance for last night’s Phil Lesh and Friends show at Terrapin Crossroads in San Rafael, CA. The guitarist played guitar for the duration of the performance (though he never sang), which recreated the Grateful Dead’s legendary May 8, 1977 concert at Cornell University’s Barton Hall. The night’s band also featured guitarists Scott Metzger and Stu Allen, keyboardist Scott Guberman, drummers Pete Lavezzoli and Alex Koford, and vocalist Jeanette Ferber in addition to Lesh and Mayer.

As previously reported, rumors have been swirling about potential collaboration between Mayer, Bob Weir and possibly other members of the Grateful Dead. Earlier this year, Billboard reported that the pair—who teamed up for a performance on the Late Show with David Letterman in February—were working on a project together, though Weir recently told us that he couldn’t say anything about it “right now.”

Phil Lesh and Friends will return to Terrapin Crossroads tonight for a second tribute to 1977. There is currently no word on whether or not Mayer will be returning for the performance.

Here’s a look at last night’s setlist:

Friday, June 12, 2015, Phil Lesh and Friends, Terrapin Crossroads, San Rafael, CA

Set I: New Minglewood Blues, Loser, El Paso, They Love Each Other, Jack Straw, Deal, Lazy Lightnin’ > Supplication, Brown Eyed Women, Mama Tried, Row Jimmy, Dancin in the Streets

Set II: Scarlet Begonias > Fire on the Mountain, Estimated Prophet, St. Stephen > Not Fade Away > St. Stephen, Morning Dew

Enc: One More Saturday Night

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