Lady Gaga has released her new single, Applause, after a number of snippets leaked online. "A pop music emergency is underway," tweeted the star as the single was distributed to iTunes and YouTube.
Applause, the singer's first new material since 2011, was originally scheduled for release on 19 August.
Leaks are almost a fact of life for today's pop stars, with Beyonce, Katy Perry and Jay-Z all seeing unauthorised material appear online this year.
Of 2013's major releases, only David Bowie managed to keep his new album under wraps.
The release of his comeback single, Where Are We Now, on the morning of his 66th birthday came as a surprise to fans and critics around the world.
Low quality clips from Gaga's record first began to appear online on Saturday.
"Lord in heaven, why?" the 27-year-old tweeted, blaming hackers for the leak. "You just couldn't wait. This is too much for one Saturday."
At first, she mobilised fans - asking them to report leaks to her record label - but by Monday evening she had relented and released the song to radio and online stores.
A short burst of robotic pop, Applause has so far received positive reviews.
Calling the single a "throwback" to her earlier material, Rolling Stone said "Applause is all bouncy disco and simple messages".
Billboard magazine said it was "built around pulsating synthesizers and morphs into a thrilling dance cut when it circles back to its chorus".
But Spin magazine said Applause "offers few reasons to clap", calling the track "bland" and "behind the times".
Lady Gaga is due to give the first performance of the single at the MTV Awards on 25 August. Her third album, ARTPOP, will be released in November.