Canadian rapper Drake has apologised to beauty mogul Kylie Jenner after referring to her as his "side-piece" in an unreleased song.

The song, a collaboration with American rapper Future, was accidentally leaked on Wednesday night (May 20), Fox News reported.

According to American tabloid Page Six, the rap lyrics that made references to Kylie read: "Yeah, I'm a hater to society... Kylie Jenner is a side-piece".

Side-piece is a slang word for mistress, commonly used to describe someone who is having an affair on the side of another relationship.

The song also referenced Kylie's sister, Kendall Jenner, and supermodel Gigi Hadid.

In an Instagram Story published on Thursday (May 21), Drake, 33, explained the mishap and insisted he would hate to have disrespected his friends, referring to the three women.

He wrote: "A song that Mark ran last night on night owl sound live set shouldn't have been played. It's a song that leaked 3 years ago and got scrapped shortly after. He was just going too deep in the drake/future catalogue. Last thing I'd want to do is wake up having any friends of mine feeling disrespected so I just had to say that to start the day."