Bob Weir and Phil Lesh shared the stage at the New York world-music club SOB’s last night. The concert marked the first time the Grateful Dead co-founders have performed together since the final Fare Thee Well show in July.

The collaboration took place during a performance by Midnight North, the California-based group that features Lesh’s son Grahame and other members of the Terrapin Crossroads community. Lesh, who is in the area for a run of shows at Port Chester, NY’s Capitol Theater, announced that he would jam with his son at SOB’s and emerged during opening act Cosmic Twang’s set for “Big Railroad Blues.” (Cosmic Twang boasts Ross James Scott Law and Grahame also sat in on the selection.)

Later in the night, Weir joined Midnight North for “West LA Fadeaway” and “Looks Like Rain.” The elder Lesh then returned to the stage and to collaborate with Weir and Midnight North on “Mr. Charlie” and “Playing in the Band.”

Weir left soon after their brief reunion, but Lesh stuck around to help Midnight North through “Cumberland Blues,” “Bird Song,” Midnight North’s “Wind & Roses” and the encore of “Unbroken Chain.” Though Weir’s sit in was unannounced, Deadheadland.com alerted fans when Weir arrived, which brought some extra bodies to the venue, including some onlookers who were attending Gregg Allman’s residency across Varick street at City Winery.

Lesh will perform at the Cap this evening while Midnight North will play an after-show at the venue’s Garcia’s space. Weir, who was in town after headlining two shows at Madison Square Garden with Dead & Company, will perform with his new outfit at Philadelphia, PA’s Wells Fargo Center tonight.