A new Michael Jackson song, the first track to emerge since the star's death, has been given its public premiere.

Few details of the track, called This Is It, were released beforehand.

It features backing vocals by Jackson's brothers, but it is not known whether they were recorded before or after the star's death in June.

The song has been released on the singer's website and to radio stations. It will be the only original song on a double CD due to be released soon.

At the time of its airing there was also no information about when the song was written and recorded, and who else worked on it.

Jackson's record label and estate declined requests for details.

It was aired on his website, michaeljackson.com, at 0400GMT on Monday and sent to radio stations and other media outlets.

Fans will be able to buy it as part of an album of the same name on 26 October.

It is likely to be the first of many new songs to see the light of day as his family and estate sift through music he left behind.

The star was working with artists like Akon and Will.i.am before his death in June.

It had been widely expected that the song would be made available to buy from digital retailers such as iTunes from Monday.

Merchandising

Jackson's official website described it as a "brand new single", which would be "released" on 12 October.

But a spokesperson said the term "released" referred to its distribution to radio stations and other media outlets.

The song takes its name from the ill-fated series of comeback shows that were to have taken place at London's O2 arena.

It will also feature in the closing credits of a film, also called This Is It, which has been made using footage of rehearsals for the O2 concerts, due to be released in cinemas on 28 October.

The BBC's Peter Bowes in Los Angeles says it was widely known that Michael Jackson had huge debts and those debts have not gone away.

But, he says, what he is hearing is the money that will be made from this single, from the movie and lots more merchandising that will take place will easily pay for all those debts and there will eventually be money left over that will go to Michael Jackson's mother and his three children.