On Sunday night, Bob Weir joined Paul Simon onstage for a take on “The Boxer” at San Francisco’s Outside Lands.

The Grateful Dead co-founder emerged at near the end of the set for the Simon & Garfunkel classic, before Simon brought the the annual festival in Golden Gate Park to a close with “American Tune” and “The Sound of Silence.” Earlier in the evening, Simon’s recent collaborators yMusic also augmented him on “Rene and Georgette Magritte With Their Dog After the War,” “Can’t Run But” and “Bridge Over Troubled Water.”

Though this marked the first time the icons of the 1960s and early ’70s have shared the stage for a duet, Simon told the crowd that he actually met Weir in 1967, when he knocked on the Dead’s door at 710 Asbury Street hoping to invite the group to perform at Monterey Pop and the guitarist answered the door.

Simon’s set at Outside Lands is one of only a handful of shows he will play in 2019, after officially retiring from extended touring last year. On Friday, he also performed a special Outside Lands “Pop-Up” show at Oakland, Calif.’s Fox Theatre and dedicated “The Boxer” to Jerry Garcia on the anniversary of his passing. Simon’s wife Edie Brickell was close with Garcia and collaborated with him during his later years.

Weir previously headlined Outside Lands with Furthur and has made a few surprise appearances over the years, most prominently with The National.