National guitarist Aaron Dessner has joined the lineup for next week’s HeadCount event, The Bridge Session. As previously reported, the benefit performance will feature a one-time-only pairing of Bob Weir, The National’s Scott and Bryan Devendorf and other members of the indie rock community. The performance will take place at Weir’s new TRI studios just north of San Francisco and will be webcast for free. Brooklyn, NY’s Littlefield will also broadcast the show. In addition to Weir, Dessner and the Devendorf brothers, the ensemble will bring together Yellowbirds’ Josh Kaufman, touring National members Thomas “Doveman” Bartlett and Kyle Resnick, The Walkmen’s Walter Martin, Yellowbirds/Apollo Sunshine’s Sam Cohen and Takka Takka’s Conrad Doucette. Disco Biscuits bassist Marc Brownstein will serve as the evening’s emcee and, between sets, a roundtable discussion will focus on issues that potentially unify people of divergent ideological perspectives. Though Scott and Bryan Devendorf are the biggest Deadheads in The National, Aaron Dessner and his brother Bryce also have deep roots in the Grateful Dead universe.