Reps for both sides — Cyrus, 20, and Hemsworth, 23, met while making the movie
Sources told E! News that the breakup was "Miley's decision, after coming to grips with Liam being what she believed was less than faithful to her."
"Liam and Miley are completely done and broken up," one insider told Us Weekly, with another saying, "She wants nothing to do with him, and vice versa. It's bad."
actor had been
by Us Weekly of sexting with actress
, a story his rep slammed as 100% false. "The story of Liam Hemsworth and January Jones is entirely fabricated ... There is no truth whatsoever to this tabloid fiction," the rep told
and other outlets last week.
No matter the cause, the couple had looked less than in love during a recent red carpet outing, their first together in about a year, the New York Daily News noted.
"I was an adult when I was supposed to be a kid," the former "Hannah Montana" says in the October issue of Bazaar. "So now I'm an adult, and I'm acting like a kid."
Probably not the best time to tie the knot, eh?