Demi Lovato fans were treated to the early unveiling of her new song, 'Heart Attack', one week before the song was due to air on Ryan Seacrest's KiisFM radio show after it was uploaded on to YouTube by her official channel.

The singer had uploaded a snippet of the new track online two week ago, but clearly this wasn't enough for the insatiable fans of the former Disney starlet. The song, produced by the Suspex, is quite a departure from the sombre 'Skyscrapers' that led off her last album, with 'Heart Attack' taking on a much more electro-pop centric sound than the first single from 2011's Unbroken. In addition to the YouTube video, Lovato also made the new single available to download from iTunes and it is believed that her upcoming fourth album, which is currently untitled, will be ready to release in spring.

Away from her own musical projects, Demi is still to confirm her place on the judging panel of the next season of The X Factor. In light of the departure of Britney Spears and La Reid from the singing contest at the end of last season, there were suspicions that Demi may follow suit, but the singer has remained silent on the subject since the last season ended. Demi joined the show along with Britney in autumn last year, with a new series of Simon Cowell's America Idol spin-off expected to air later this year.

Listen to 'Heart Attack' below.