Christina Grimmie, who starred in season six of the US version of television show The Voice, was shot in Orlando as she signed autographs at a merchandise table.
The 22-year-old from New Jersey was targeted by a gunman at The Plaza Live concert venue in the centre of the city late on Friday night.
Heather Walsh, a publicist for Grimmie, said: "We can confirm that Christina has passed and went home to be with the Lord".
With deep regret, we have confirmed Christina Grimmie, @TheRealGrimmie has died from her injuries.
— Orlando Police (@OrlandoPolice) June 11, 2016
Grimmie spoke openly about her Christian faith, writing on her website earlier this year: "Jesus is the only one that can save us. He is the only one that has taken our penalty. He is the bridge that allows us to be restored in Spirit with God."
Police have credited Grimmie's brother with preventing further casualties after he tackled the perpetrator, however, officers are yet to reveal the gunman's identity of his motive.
The singer amassed 3.1m followers on the video-sharing website, YouTube, and her singles included the tracks "Shrug", "Cliché" and "Must Be Love".
In a tribute to Grimme on its official Twitter page, The Voice said: "There are no words. We lost a beautiful soul with an amazing voice."
There are no words. We lost a beautiful soul with an amazing voice. Our hearts go out to the friends, fans and family of @TheRealGrimmie.
— The Voice (@NBCTheVoice) June 11, 2016
#RIPChristina has been trending on the social media website, with more than half a million tweets posted using the hashtag.