The New York Post reports that music pirates "stole" pop star Madonna's brand-new single and played it over the Internet - four months before its release.
The star's record company has threatened legal action against any website that allows Music, which is still in production, to be downloaded.
MTV's online site offered a segment of the song to surfers.
"The music was stolen and was not intended for release for several months. It is still a work in progress," her manager, Ms Caresse Norman, said.
"Ultimately, those sites that offered a download of Madonna's music are violating her rights as an artist."
Warner Bros Records, which distributes her recordings, called the early release "an extremely serious matter".
A spokeswoman for Madonna, Ms Liz Rosenberg, said the superstar was surprised by the breach of security.
"Her work was stolen. I don't think any artist likes it when that happens," Ms Rosenberg said. Madonna's new album is due for official release in late September or early October.