is leaving The X Factor
, a source close to the singer tells PEOPLE.
The reason? "She plans to spend next year completely focused on her music," says the source.
"She had a great run and a good time," says the source. But the show's demanding schedule conflicts with the singer's plans for 2014.
Lovato, 21, who has served as a judge for two seasons, is about to headline her first arena tour, which kicks off Feb. 9 in Vancouver and will also feature X Factor
alums Cher Lloyd, Little Mix and Fifth Harmony.
In November, Lovato, who had a guest stint
earlier this year, talked about her current priorities
"I think ultimately my main thing is singing," she said. "Maybe movies once in a while, if the right role comes along."
She added that she also wouldn't mind a little bit of a break.
"I will take the month of January completely off!" she vowed. "I want to vacation! I want to watch crime shows on my DVR on my couch ... I need to do some exercising and I don't really have time to do it. I love horseback riding and never get to do that stuff, but January is my time to do all of that."