The kind-hearted music mogul tweeted the 20-year-old pop star after she was forced to miss a photocall for the show after learning that dad Patrick had died.
Simon wrote, "My thoughts are with you Demi X", after she missed the shoot with him and her fellow judges Cowell, Kelly Rowland and Paulina Rubio.
Simon Cowell Tweets Condolences To Demi Lovato After Her Father Dies
Demi Lovato's estranged father Patrick has passed away (WENN)
The show's host Mario Lopez posted a snap from the shoot on his Twitter page and wrote: "With my @TheXFactorUSA team! Missing @ddlovato today... :("
Demi's sister Dallas posted a message just moments earlier that read: "Rest in peace Daddy, I love you..."
Both Demi and Dallas wer estranged from their father who has been battling cancer in recent years, although the actual cause of death has yet to be revealed.
My thoughts are with you Demi. X— Simon Cowell (@SimonCowell) June 23, 2013
Patrick divorced Demi's mother Dianna when she was a little girl and the pair have been estranged ever since.
In February last year, she spoke about a song on her third album called For The Love of a Daughter which hinted that Patrick may have had a problem with alcohol.
Speaking to the Daily Mail, she said: "It’s a very personal song. 'Oh father, please father, put the bottle down…' The lyrics are self-explanatory about my relationship with my estranged father whom I haven’t spoken to in five years. I wrote it when I was 16 and getting it out is like therapy."
Patrick tried to reach out to her in 2011 via the media and told Radar Online: "I love her so much, and I just want her to call me. This is the only way I can talk to her, I try to reach her but it never works."
See a video of Patrick talking about his famous daughter to Inside Edition in 2010. Our thoughts are with Demi and her family at this sad time.
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