The former Pussycat Doll singer wants to focus on her music and is said to be "heartbroken" after spending months "agonising" over the difficult decision.
"She put her music career on hold last year but now she wants to focus on her music," a source told The Sun.
Nicole’s move comes amid rumours that she has rekindled her romance with her ex, Formula1 driver Lewis Hamilton.
The pair were seen this week heading hand-in-hand to a central London restaurant.
Nicole, 35, and 29-year-old Lewis also showed that love is back on the cards when they posted a series of snaps on their Instagram accounts of their winter wonderland adventure in Aspen over the New Year, suggesting that the couple have reunited after their split several months ago.
While music mogul Simon Cowell will be one judge down for the next series, he spoke this week about the possibility that Cheryl Cole will be on the judging panel of the next series of the ITV talent show.
The pair, who have been in talks about Cheryl’s return, have had a contentious relationship since she was famously axed from the US version of The X Factor in 2011.
Dad-to-be Simon will also be returning to the panel of judges for the eleventh series of the UK talent show for the first time after a three-year absence from the show.