BISMARCK, N.D. (AP) — Musician Dave Matthews and actors Shailene Woodley and Mark Ruffalo are encouraging Native Americans to vote.

The Stand-N-Vote campaign launched Wednesday features the actors and American Indian comedian Auntie Beachress announcing a concert Saturday by Matthews and Ruffalo on the Standing Rock reservation.

Organizers say the effort is in response to a U.S. Supreme Court decision this month upholding North Dakota’s voter ID law, which requires a street address to vote. Many living on reservations have post office boxes and argue the law discriminates against Native Americans.

The concert will be livestreamed and tribal officials will be attending to provide required IDs. Organizers say additional events will be scheduled at other North Dakota reservations.

Woodley, Ruffalo and Matthews each spent time two years ago protesting the Dakota Access oil pipeline.