John Travolta has been keeping a low profile online over the past few weeks, but returned with an upbeat post over the weekend.MORE: John Travolta's daughter Ella shares rare glimpse inside family homeThe Grease star took to Instagram to share a black-and-white picture of himself with Sammy Hagar, as they enjoyed a tequila shot at the rock star's nightclub, Cabo Wabo.The pair were all smiles as they posed for the photo, which was captioned: "My evening with a rock legend.