Jonas, 23, who was in Florida for his world tour went for a trip to Disney World in Orlando and was spotted by a fan while riding a roller coaster alongside Hudson, reported E! Online.
Hudson, 36, and the singer were spotted brunching in Miami on Sunday.
"The buzz is that they were acting like a couple. They were definitely there together. They made an effort to keep things under wraps, using the private pool for members that's harder for regular guests-and paparazzi-to get glimpses of," a source said.