The song was touted as previously unreleased material from Jackson when it was posted online Monday morning, months after the pop icon died at the age of 50 from an overdose of the anesthesia propofol.
Anka, who is best known for writing the classic song "My Way," swiftly threatened to sue Jackson's estate because it didn't credit or pay him for "This Is It," which he said he co-wrote with Jackson in 1983, E! News said.
Anka said Jackson's estate administrator John McClain got in touch with him Monday afternoon, apologized for the oversight and offered to split the proceeds from the song's sale and the publishing rights to it with him.
"I said: 'It's fine if it's an honest mistake. These things happen,'" Anka told The New York Times.
Anka said his collaboration with Jackson was to appear on his album "Walk a Fine Line," but it wasn't used then after the two artists had a falling out.
"The song was picked because the lyrics were appropriate because of the name Michael gave his tour," McClain and co-administrator John Branca said in a statement referring to why the single was chosen to be Jackson's first posthumous release. "We are thrilled to present this song in Michael's voice for the first time, and that Michael's fans have responded in unprecedented numbers. The song was co-written by the legendary Paul Anka."