Producer Sues Paul Anka and Michael Jackson Estate

The producer -- named Michael Jonzun -- filed the lawsuit in Massachusetts federal court, claiming he helped remake Paul and MJ's 1983 song "I Never Heard" ... into what eventually became MJ's 2009 song "This Is It."

According to the lawsuit, Jonzun owns one-third of "This Is It" but he never got paid his share of the song's proceeds -- so he's suing.