Justin Bieber duets with Usher in Las Vegas

Justin Bieber returned from illness to put on a star-studded show in Las Vegas on Sunday night (30Sep12), performing with both Usher and Carly Rae Jepsen.

The Baby hitmaker struggled through the first date of his Believe tour in Arizona on Saturday (29Sep12) after he fell sick and vomited on stage.

He refused to let his ill health affect his tour and was back on stage at the MGM Grand Garden Arena in Sin City a day later.

Bieber looked to be back on form and he thrilled the crowd by performing Somebody To Love with his mentor, Usher, while he also sang with his support act Jepsen on their duet Beautiful.

After the show, Bieber wrote in a post on his Twitter.com page, "Did it big in Vegas 2nite (tonight) with big bro (sic) Usher... Expect the unexpected on the Believe Tour."

Socialite Paris Hilton was in the audience at the concert and she was full of praise for the young pop star, tweeting, "So much fun at Justin Bieber's concert... He's such an amazing performer!"