Britney Spears (AFP photo)

A disgruntled contestant rejected from America's The X Factor has taken out his anger on judge Britney Spears by leaking one of the pop star's never-before-heard songs.

Don Philip, who duetted with Spears on her debut album, ...Baby One More Time, was among the hopefuls who tried out for the hitmaker and her fellow talent show judges in San Francisco, California last month, but he was dismissed from the competition after failing to win over the panel with his performance.

The aspiring star later lashed out at the 30 year old, poking fun at her past mental health problems on Facebook.com, and now he has released a previously-unheard Spears demo on his SoundCloud music-streaming account.

The song, originally entitled Pleasure You, also features Philip's vocals.

The wannabe's audition was an emotional one because he chose the try-out to 'come out' as a gay man.