Cheryl Fernandez-Versini is leaving the X Factor to focus on her music career.
The 32-year-old said in a statement: "I have had such an amazing experience being a judge on the X Factor.
"I have learnt so much and enjoyed nurturing talent but I've missed making music and am excited to be recording again.
"I want to thank everybody I have worked with along the way, especially Simon, who I love to bits. I hope the show continues to produce stars and I wish them all the best."
The show's boss, Simon Cowell, said: "Cheryl and myself spoke about this. I totally understand her commitment to making more records. She has been amazing on the show, and in the near future we will be working on other things together."
She has started working on a new album which is due for release later this year.
The former Girls Aloud singer joined the talent show in 2008 and two of her acts went on to win the show - Alexandra Burke and Joe McElderry.
She left the judging line-up in 2010 before returning again in 2014.
She mentored last year's runners-up, Reggie N Bollie, who finished behind 17-year-old Louisa Johnson.
Her exit follows the news that DJ Nick Grimshaw will not be returning as a judge.
The show's presenters, Caroline Flack and Olly Murs, also confirmed they would not return.