LOS ANGELES (Reuters) - Pop star Britney Spears on Friday called it quits with both fiancé Jason Trawick and as a celebrity judge on "The X Factor" talent show.

Spears, 31, and Trawick, 41 - her former agent - got engaged in December 2011.

"Jason and I have decided to call off our engagement," Spears said in a statement. "I'll always adore him and we will remain great friends."

The couple began dating in May 2010, following a turbulent few years in Spears' personal and professional life in which she lost custody of her children, entered rehab and shaved off her hair.

Trawick added in a statement: "As this chapter ends for us a new one begins. I love and cherish her and her boys and we will be close forever."

The wedding would have been the third for Spears. She divorced dancer Kevin Federline, with whom she had two children, in 2006.

The singer also spontaneously married childhood friend Jason Alexander during a trip to Las Vegas in 2004. That marriage lasted 55 hours before the singer annulled the union.

Spears and Trawick announced their split the same day that the "Toxic" singer confirmed she was leaving "The X Factor" after just one year as a judge on the Fox singing show, saying it was time to get back to making music.

"I had an incredible time doing the show and I love the other judges and I am so proud of my teens but it's time for me to get back in the studio.

"Watching them all do their thing up on that stage every week made me miss performing so much! I can't wait to get back out there and do what I love most," Spears said of her "X Factor" departure.

Spears' most recent album, "Femme Fatale," was released in March 2011.

Celebrity website TMZ.com reported on Friday that Spears was in talks about a long-term residency gig in Las Vegas. The gambling city is already host to stars like Celine Dion and Shania Twain, who perform under long term contracts.

Spears was recruited to "The X Factor" with a reported $15 million salary after a 14-year singing career that made her one of the biggest pop stars of the 2000s.

But audiences slumped and the TV show lost about 3 million regular viewers from its first season. Many fans and TV critics found Spears bland and boring.

The exit of Spears leaves "X Factor" creator Simon Cowell searching for two new judges to lift his show past its NBC rival, "The Voice," in the ratings when it returns in September.

Judge and record producer L.A. Reid announced in December that he would be returning full time to his job as the head of Epic Records.

Spears took "The X Factor" gig with singer Demi Lovato, 20, in May 2012 to fill the judges' seats left by Paula Abdul and Nicole Scherzinger, who were both fired by Cowell a year ago.