A man opened fire on her when she was signing autographs after a concert in Orlando. The 22-year-old singer died in a local hospital.
The assailant -- who was tackled by Grimmie's brother -- then shot and killed himself, reported E! online.
In 2014, Grimmie finished third during season six of The Voice.
In a tweet, Orlando's police wrote: "With deep regret, we have confirmed Christina Grimmie, @TheRealGrimmie has died from her injuries."
Meanwhile, Grimmie's publicist said: "It is with a heavy heart that we can confirm that Christina has passed and went home to be with the Lord."
A police investigation is now under way into how the suspect had managed to enter the venue with the firearms. News of the attack spread quickly on social media, with many fans voicing their shock and anger.
Grimmie first came to prominence as a teenager for her renditions of hit songs, amassing a huge following on Youtube.
In 2011, she released her debut musical recording Find Me. Her second EP - Side A - followed in February 2016.
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