The bout was supposed to be all about the Ukrainian champion stepping up and showing what he’s made of against the world’s best.
But it has been marred by a doping scandal after Usyk’s original opponent Tyrone Spong was found to have failed a test by the Voluntary Anti-Doping Association (Vada).
This heavyweight bout will take place on Saturday, October 12 from around 10pm in USA.
That is 4am BST on Sunday, October 13 UK time.
The event will be held at the Wintrust Arena in Chicago.
Usyk vs Witherspoon will be shown live on Sky Sports Main Event and Sky Sports Action from 2am on Sunday.
Sky Sports customers can live stream this via the app on their computer, mobile and tablet devices.
If not, you can purchase a Sky Sports Day Pass from NowTV for
Usyk was scheduled to take on Tyrone Spong in the main event of the show. But on Monday night, it was revealed that Spong had tested positive for a banned substance.