Authorship of "This is it"

"This is it", billed as Michael Jackson's new song, is a song that Jackson had written with Paul Anka around the time of Thriller [ca. 1983] and which had previously been released as "I Never Heard." [Safire, 1991].

Everyone is on the same page now, so no big litigations are in the offing. [Note
AmericanSongwriter: "Eventually, after legal action was threatened, administrators of Jackson’s estate agreed to award Anka 50 percent of the publishing rights.
"]

One can listen to the version by Safire.