Cowell pays tribute to Simone Battle, who died aged 25
Simon Cowell has paid tribute to Simone Battle following the death of the former X-Factor USA contestant.
The 25-year-old, a member of US girl group G.R.L., was found dead at her home on Friday.
Authorities in Los Angeles haven't yet revealed the cause and a post-mortem is expected to take place on Sunday.
Cowell, who was the singer's mentor when she appeared on X-Factor USA, tweeted: "She was such a fun nice person. It's such a loss."
Her bandmates in G.R.L. also paid their own tribute.
"Words cannot express the depth of our loss," they posted on Twitter. "Simone's incredible talent was only surpassed by the size of her heart."
A joint statement from Reign Deer Entertainment, Robin Antin, Kemosabe Records, and RCA Records read: "We are deeply saddened by the tragic news of the loss of Simone Battle of G.R.L.
"Simone was an exceptional young talent and human being, and we are all devastated to learn of her passing.
"Our thoughts and prayers are with her family and loved ones at this time."
After appearing on X-Factor, Battle was originally part of the line-up for a rebooted version of the Pussycat Dolls, put together by the Dolls' original creator Robin Antin.
A few line-up changes later and that group eventually became G.R.L.
G.R.L. are on course to enter the top five of the UK's Official Chart with their single Ugly Heart.
In 2011, Battle appeared on the first series of the US X-Factor, performing in front of judges including Simon Cowell and Paula Abdul.
She progressed to the live finals of the show as part of Simon's category.
Cheryl Fernandez-Versini's among those who've paid tribute. She tweeted: "Such tragically sad news to hear of the passing of Simone Battle. My thoughts and prayers are with her loved ones."
Another tribute came from former member of the Pussycat Dolls Kimberley Wyatt who tweeted "In disbelief... My heart hurts for her friends, family, and bandmates."
One of her friends, Derek Butler, posted a picture of her on Instagram with the comment "I'm still in shock and in disbelief to have confirmed the death of my childhood friend Simone Battle.
"Her heart was pure gold and her star power limitless."