The TV titan, one of America's highest earning celebrities, is being sued by author Damon Lloyd Goffe who accuses the media mogul and her production company Harpo Inc. of plagiarising his book A Tome of Poetry in her internet published work Pieces of my Soul.
And in a copyright infringement suit filed at the District of Columbia Court on 31 July, Goffe insists Winfrey even admitted she used his original works in 2008, reports the National Enquirer.
In the documents, he writes, "In April 2008 Oprah confessed to seizing original works of authorship".
Goffe and his legal team are seeking the huge amount in damages, claiming that as Winfrey sold an alleged 650 million copies of the book online for $20 (£13) a time, he is owed $1.2 trillion.
However, Goffe admits that the website, which sold Winfrey's work, is no longer available.
A representative for Winfrey has not commented on the case as WENN goes to press.