During a recent interview with Ellen DeGeneres, the ginger singer was asked about the ex-girlfriend behind the tune and his answer was pretty shocking.
"You know what, with that song it was just that I'm quite a happy, carefree guy and I feel like everybody goes through things and gets angry, and I feel that the way I get my anger out is to write songs and that song was literally that I felt something, I put it down and I felt better afterwards," he told her.
"I wasn't going to put it on the record, then people kept telling me it was an alright song. So it ended up on the record, but yeah that one is a bit personal."
See more specifically who he said "Don't" is about in the clip below. Surprised?