Teen star Demi Lovato has sealed her comeback after her first shows since her stint in rehab last year sold out in a matter of minutes.

The singer and actress underwent three months of treatment for a series of emotional issues, including self-harming and an eating disorder.

She announced a trio of shows earlier this month her first since she quit her South American trek with the Jonas Brothers in 2010. The three gigs sold out in less than 15 minutes.

She took to her Twitter page to thank fans, writing, "Wow. Thank You Guys!!!!!! I have the best fans ever ever Ever!"

Lovato will play two shows at the Hammerstein Ballroom in New York on September 17 and 18 and a third gig at the Nokia Theatre in Los Angeles on September 23.

Watch Demi Lovato on T4 here: