The music mogul praised Nicole on Twitter in the early hours of this morning (14 February), telling fans that she will "always be a part of the X Factor family".
Simon's message of support follows recent speculation that 'Boomerang' singer Nicole will now focus on her music.
Simon, who also worked with Nicole on X Factor US in 2011, said: "Nicole will always be a part of the X Factor family. Now signed to Sony as an artist. Thank you Nicole for everything."
This week, reports claimed that 35-year-old Nicole was to step away from the show to focus on her music career.
Nicole will always be a part of the X factor family. Now signed to Sony as an artist. Thank you Nicole for everything.— Simon Cowell (@SimonCowell) February 14, 2014
Nicole is yet to make an official comment but she did promise fans during the Xtra Factor's final episode last year that she would be making new music soon. Following that, former Pussycat Doll Nicole was pictured in the recording studio last month, working on the follow-up to her 2011 album Killer Love.
Nicole has had a very successful run on The X Factor after having both acts Jahmene Douglas and James Arthur in the 2012 final, with James eventually winning. Last year, Nicole mentored the girls category but her three acts narrowly missed out on a place in the final.
Meanwhile, Simon confirmed his return as head judge to the ITV talent show last week and has since told Reveal that he wants Cheryl to make a return to the judging panel following her departure in 2011.
"I think she'd be crazy not to come back, but you never know with her," he told us. "I'm hopeful that we can do something, but people get cold feet and it's a big big commitment, so we'll have to wait and see."
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