Janelle Monae made a surprise performance at Bravo chef Roblé Ali’s Everyday People Brunch bash on Saturday. The diva was on hand to introduce Deep Cotton — the band she’s producing — but then she hit the stage herself for a set at the DL on the Lower East Side. “Deep Cotton killed it,” said a spy, “and then Janelle did an unplanned, impromptu concert herself, including several tracks from her new album.” Rumors also burbled at the brunch that Monae could pop up at City Winery during Purple Week, the residency by Prince’s backing band New Power Generation.