The massive Chicago festival begins today, with headliners Charli XCX, Tate McRae, Lorde, Olivia Dean, John Summit, Jennie, the xx and hometown heroes the Smashing Pumpkins. And Barry Williams was there — the Barry Williams who played Greg Brady on The Brady Bunch. He joined the Pumpkins onstage to perform "It's A Sunshine Day," the Brady Bunch hit written by Steve McCarthy. Or maybe the Smashing Pumpkins are diehard Brady Bunch fans. Not only are the Smashing Pumpkins making the great return to Lollapalooza, but they've secured a spot among the stars next year.