Christina Grimmie was just 19 when she auditioned for the sixth season of The Voice, which aired in 2014.
Three of the judges turned around in the first few bars of her rendition of Miley Cyrus' Wrecking Ball.
She chose Maroon 5 lead singer Adam Levine as her coach, and came in third place on the American reality television singing contest.
At 22, her showbiz career was just taking off when she was shot while signing autographs for fans after an Orlando concert.
Her brother tackled the gunman, who shot and killed himself.
Even before appearing on The Voice, the New Jersey native had a large following on her YouTube channel zeldaxlove64. She now has more than 3 million followers.
Some of Grimmie's covers of popular songs have tens of millions of views, and a video of her duet of Just A Dream with fellow YouTube musician Sam Tsui, has more than 116 million views.
She was called the next Justin Bieber by some, who expected her, like Bieber, to become a YouTube breakout star.
She toured with US singer-actress Selena Gomez in 2011 and 2014.
Fans and musicians she worked with were shocked at the apparent senseless shooting and tributes poured in for the young singer.
Before her death was confirmed, Levine posted a photo of himself and Grimmie on Instagram saying: "I'm sad, shocked and confused. We love you so much Grimmie. We are all praying hard that you can pull through this...this just isn't fair."
Shortly after the news of her death was confirmed, Before You Exit, the band that was performing with her in Orlando tweeted: "Today we lost an angel, sister, and a beloved friend. #RipChristina"
The Voice also paid tribute to the singer on its official Twitter feed: "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 National University of Singapore sent its condolences as well: "Shocked & sad. Christina sang at NUSSU Rag 2015. Thoughts & prayers with her family, friends & fans. #RIPChristina"
Hashtags #RIPChristina and #PrayForChristina were both trending on Twitter on Saturday.
Netizens were also sharing a video of her last performance.
Grimmie's last tweet, asking fans to attend her concert in Plaza Live in Orlando, has amassed thousands of responses from heartbroken fans.https://twitter.com/TheRealGrimmie/status/741387106921140224