Michael Jackson's new song is set to receive its first airplay, nearly four months after the King of Pop's death.
The track has the same name as Jackson's 50-date comeback concerts, which had been due to kick off in London over the summer.
The song is being delivered to radio stations amid tight security.
BBC Radio 1 has confirmed it will be one of the stations to play the track.
Featuring the backing vocals of the late singer's brothers, it will be included in a two-disc album, also called This Is It, to be released later this month.
The album contains songs included in a documentary about the singer, who died in June aged 50.
It will hit the shops on October 26, to coincide with the worldwide release of the film.
The first disc will boast the original album masters of some of Jackson's biggest hits, arranged in the same sequence as they appear in the film. The disc will end with two versions of This Is It, which features in the film's closing sequence.
The second disc contains previously-unreleased versions of some of the artist's classic tracks and a "touching" spoken word poem titled Planet Earth.
John McClain, co-producer of the album, has said of the new track: "This song only defines, once again, what the world already knows - that Michael is one of God's greatest gifts."