According to People, the actress and singer was seen having drinks with former NFL player Johnson at Florida's Ponte Vedra Inn & Club.
They were reportedly later seen together at an airport in Jacksonville where one observer described them as being "huggy-kissy" at the ticket counter.
Another source added: "They were holding hands and she was rubbing his back and scratching his head. They were affectionate."
Simpson and Johnson - who has played for the San Francisco 49ers and the New Orleans Saints - are thought to have been dating since May but neither has commented on the relationship.