A source told the US gossip website: "It was just casual at first, but things are getting pretty hot and heavy,”

It is thought that GaGa and Taylor - who also stars in hit TV show Vampire Diaries - were spotted "getting steamy" in a beachside bar in Mission Viejo, California, with an onlooker stating: "I couldn’t tell it was her at first. It just looked like some hot couple making out."

"But then I realized it was Lady GaGa! Everyone went nuts! She was so sweet too -- she even signed some autographs.”

The eyewitness added: "Her hair was a little messy. It definitely seemed like a ‘morning after’ situation. They are obviously totally into each other!”

The Judas hitmaker and Kinney were then reportedly caught holding hands on Mission Boulevard on Monday, before hitting the beach the day after.