"This is It" premiered on Jackson's official Web site www.MichaelJackson.com at midnight EDT (0400 GMT Monday). The mid-tempo number features Jackson's trademark vocal style,background vocals from his brothers and some orchestral backing.

A documentary on Jackson also called "This is It" opens Oct. 28 for a limited two-week run. It shows footage of the singer rehearsing for his planned London concerts, which never happened because of his sudden death on June 25.

The song appears in the documentary's closing sequences and will be included in the two-disc CD set that accompanies the movie.