The duo, who were spotted making out at a nightclub in Las Vegas last week after recently enjoying a trip to the Bahamas together, are dating but the 'Twilight Saga' actor isn't comfortable with the amount of attention their casual romance is attracting.
A source told E! News that the pair are an "item" but insisted they aren't serious because Miley, 21, is more interested in Kellan, 28, who was good friends with her ex-fiancé, Liam Hemsworth, whom she split from in September after four years together.
The source added: "She likes him a lot. There are a lot of similarities between Kellan and Liam. He is her type."
A source close to the 'Wrecking Ball' hitmaker previously claimed that she had invited Kellan to be her special guest at her performance on 'Dick Clark's New Year's Rockin' Eve With Ryan Seacrest' in New York City on Tuesday night (31.12.13) but the actor opted to ring in 2014 with friends on the Caribbean island of Grenada instead.
The singer was all over her new beau at Beacher's Madhouse in Las Vegas last Friday (27.12.13), despite initially attempting to keep her distance from him at the club's grand opening.
An eyewitness previously said: "They talked at very close range for a long time while Miley was laughing and rubbing his back. At one point she kissed his ear."