A previously unreleased song by Michael Jackson entitled "This is It" was unveiled to the world Monday almost four months after the star's death.

The track was released at the stroke of midnight at michaeljackson.com, marking "yet another exciting moment in music history for one of the world's most revered artists," Sony Music Entertainment said in a statement.

The recording features backing vocals by Michael's brothers and will be played during the closing sequence of the forthcoming film Michael Jackson's This is It and feature on a two-disc CD set of the same name.

A new photo of Jackson taken during rehearsals at the Staples Center in Los Angeles will also be unveiled, the record label said.

The album will go on sale later this month to coincide with the October 28 worldwide release of the movie.

The song was reportedly written in 1980, which might explain the lyrical similarities to some of the yearning hits on Jackson's early solo albums like “Off the Wall” and “Thriller,” though, betray it as a late-period song, more in line with such emotional ballads as "Man in the Mirror" and "Gone Too Soon," from 1987.

"This is It" may be the first of many previously unreleased Jackson songs that will be issued in the wake of the singer's death, with reports that there are 100 or more tunes in the vault that fans have not heard.

Disc one of the album features some of Jackson's biggest hits such as "Billie Jean," "Human Nature" and "Thriller."?

The disc ends with two versions of "This is It", the original and an orchestral one.

Disc two offers fans the early demo versions of classics "She's Out Of My Life," "Wanna Be Startin'' Somethin',"?and "Beat It."?

The film will offer a behind-the-scenes look at the performer as he rehearsed for his sold-out concerts that would have taken place this year in London, Sony said.

Chronicling the months from March through June 2009, the film is drawn from more than 100 hours of behind-the-scenes footage, featuring Jackson rehearsing a number of his songs for the show.

Jackson died June 25 at age 50 after taking a lethal cocktail of prescription drugs. The coroner's office has ruled his death a homicide, but prosecutors have not filed charges so far.