The 20-year-old singer said he needs to "take responsibility" for new footage, filmed when he was 14, reported Contactmusic.
"At the end of the day I just need to step up and own what I did. Facing my mistakes from years ago has been one of the hardest things I've ever dealt with. But I feel now that I need to take responsibility for those mistakes and not let them linger," he said.
The star's latest apology comes just days after he was forced to say sorry when another video of him telling a racist joke was published online.