Singer gest personal during BBC Radio 1 interview, during which Selena Gomez, Joe Jonas and Jack Black also chime in.
The singer and actor gave his thoughts and feelings on the song this week while hooked up to a heart rate monitor for a hilarious interview on BBC Radio 1.
Although Cyrus, who the Jonas bro dated for two-and-a-half years, never directly confirmed those rumors that she wrote the track about him, the "Jumanji" star said there is enough evidence in the music video to convince him that it's true.
"She's wearing the dog tag in this thing that I gave her when I was 14 or something," Jonas said.
But despite all odds, Jonas was actually "kind of flattered" that she wrote a break up jam about him, and even called it a "good song."
"It's there forever and I know it's about me," he said.
The game is simple: BBC hosts asked Jonas questions while monitoring his heartbeat, but then his famous friends chimed in to ask him questions or dare him to spill on personal moments in his life.
"She's a huge fan of yours," Black said. "She's asking if you want to ride the dragon tonight."