Demi Lovato to Leave 'Sonny with a Chance'

Disney darling Demi Lovato will not be returning to her hit show "Sonny with a Chance."

"It made sense for me to go ahead and leave the show to focus on my music," Lovato, 18, tells People magazine in this week's issue. "It's kind of sad for me that a chapter of my life has ended but there couldn't be a better time for me to move on," she added.  

In the Disney Channel show, Lovato plays Sonny, a talented Midwestern girl who wins a nationwide talent search and moves to Los Angeles to star in a popular television series.

A Disney rep told ET: "We respect Demi's decision to focus full-time on her music and not immediately return to her acting career. She is a talented young woman and our hearts are with her as she continues to take action to improve her health and bounce back from adversity."

Last November, Lovato pulled out of her concert tour with the Jonas Brothers "to seek medical treatment for emotional and physical issues she has dealt with for some time." Pictures of the young star emerged in January and a source confirmed to ET at that time that she had completed her prescribed treatment.