No performer is perfect, and Justin Bieber is no exception.

The 18-year-old heartthrob grew sick while performing in Glendale, Arizona on Sept. 29. Bieber turned his back to the audience while singing "Out of Town Girl," hunched over, puked and ran off the stage.

If you have a strong stomach, click here to watch TMZ's footage of the event. 

But Bieber didn't want to disappoint his fans and came back on stage, saying: "It's hard for me, you know, not feeling great and throwing up in front of a bunch of people. Will you love me even though I'm throwing up on stage?"

Apparently his fans didn't mind -- the sold-out crowd screamed for more.

"OK. I wanted to give you my best show ever, so do you mind if I finish it?" 

After his performance, Bieber took to Twitter and wrote, "Great show. Getting better for tomorrow's show !!!! Love u" and then confessed, "And .... Milk was a bad choice! Lol"

During his Arizona performance he dedicated his song "One Less Lonely Girl" to Avalannna Routh, a 6-year-old fan who died of cancer on Sept. 26, reported Us Weekly. While looking up he said, "If you're listening, I love you."

According to Us Weekly, on Valentine's Day, Routh and Bieber had a pretend wedding.

After Bieber met with his young fan, the singer tweeted, "That was one of the best things I have ever done. She was awesome! Feeling really inspired now! Mrs. Bieber."

They continued to keep in touch after their Valentine's Day visit. On Sept. 13, Routh tweeted Bieber, "Trying to stay up late to see my husband on Americas Got Talent. Supporting my man. Mrs. Bieber."