Justin Bieber has opened up on his recent on-stage vomit incident.

The Canadian star was filmed throwing up on stage whilst performing in Arizona on Saturday (September 29), with the clip soon becoming a hit online.

He was seen turning his back on the crowd before blowing chunks onto the stage and then running backstage.

Speaking to TMZ, Bieber said that a mixture of spaghetti and milk prior to the show must have upset his stomach. The 'Boyfriend' star said:

"Basically, in Canada we like to have spaghetti with milk. I don't know if it was such a good idea just before my show but I had a glass of milk before I went on stage and I was feeling it like five songs in."

He continued: "Going on stage after that was not a good idea but it was great, the show still went smoothly after that. I went back out there and finished it and gave them a great show."

Watch Bieber throw up below: