Last week, Chance announced that he's formed a formal event-production company, Social Function Productions, and will help organize a 50th anniversary celebration concert for Special Olympics, which were first held at Solider Field in 1968. The concert will take place at the Huntington Bank Pavilion on Northerly Island on July 21, beginning at 5 PM. Much of the lineup remains a mystery, but Chance revealed that Motown legend Smokey Robinson, pop singer-songwriter Jason Mraz, and alt-rockers OAR will perform.

The show poster that Chance tweeted leaves room for four more unannounced headlining acts that will likely be revealed in the coming weeks. It's not too much of a stretch to assume that Chance will be involved, even if he doesn't formally headline the concert—the only tour dates currently on his summer schedule are in August. Those with tickets to Pitchfork Music Festival, which occurs during the same weekend, will have to choose between seeing Fleet Foxes and the War on Drugs, or leaving Union Park early to make the trek to Northerly Island. Tickets for the Special Olympics 50th Anniversary Concert are on sale now here, with prices ranging from $50 for lawn seats to $150 for general-admission pit tickets.