Demi Lovato is reportedly leaving the "X Factor" to focus on her music career and prepare for her upcoming "Neon Lights" tour. A source told US Weekly, that the 21-year-old singer has decided not to return for Season 4 as a judge. That means Simon Cowell, Kelly Rowland and Paulina Rubio will be shy one less judge when the new season premieres.

"She has a great time but she's going to focus on her music next year," the source said.

Lovato has been so busy with the FOX singing competition show and her guest role on "Glee" that she hasn't had the time to tour or promote her latest studio album "Demi," released in May 2013. The "Neon Lights" tour will kick off in February 2014 with Lovato, British girl group Firth Harmony, Little Mix and Cher Lloyd.

"To be in the same atmosphere as [Demi] is so awesome," Fifth Harmony told Fuse. "We really look up to her. She's one of our role models. When she asked us to be on tour, it was like, 'Oh my god, absolutely."

Lovato recently opened up about her struggles with cocaine to "Access Hollywood." It was the first time the "Skyscrapper" singer revealed how serious her drug addiction was. She said that she was able to keep it hidden from everyone around her, including a sober companion who traveled and lived with her.

"Something I've never talked about before, but my drug use I could hide it to where I would sneak drugs," she said in the interview. "I couldn't go 30 minutes to an hour without cocaine and I would bring it on airplanes."

"I would smuggle it basically and just wait until everyone in first class would go to sleep and I would do it right there," she continued. "I'd sneak to the bathroom and I'd do it."

The "Heart Attack" singer she realized at 19-years-old that her life was on a downward spiral and knew she needed to make some serious changes. Besides an intense drug addiction she also said she was abusing alcohol.

"I had a moment where I was like, 'Oh my God... that is alcoholic behavior," she said. "[It's] no longer, 'I'm young and rebellious and having fun,' it was, 'Wow, I'm one of those people... I gotta get my shit together."