Bob Weir didn’t end up performing with pop star Justin Bieber—Weir was backstage at the show with his young daughter and Bieber’s “exciting news” had to do with taping an episode of CSI —but the Grateful Dead guitarist has confirmed an unlikely collaboration: he will perform with The Marin Symphony at California’s Veterans Memorial Auditorium on October 22.

“First Fusion,” the 41-piece orchestra’s first collaboration with a rock musician, will feature two distinct segments. The first part of the evening will feature Dead material rearranged for the orchestra by Weir, the evening’s conductor Giancarlo Aquilanti and the Stanford Wind Ensemble. The second part of the show will include an improvisational segment boasting Weir, members of The Marin Symphony and, according to the Marin Independent Journal, possibly additional members of RatDog. Furthur will return to the road later this week for performances in New York and Bridgeport, CT.