Katy Perry partied incognito in the Hamptons over Memorial Day weekend. The sexy singer was seen at raucous club South Pointe with a large group Saturday. But, a spy said, “It was hard to recognize Katy because she had on an oversize beach hat, with big glasses and a long baggy dress.” The spy added that Perry’s posse started their night “outside in a cabana,” then asked to be moved to a table next to the DJ, Chris Lake, where Perry was seen dancing the night away.