McAllister will face ring great Williams in a heavyweight showdaown at the Beach Ballroom on Saturday July 28.
The 35-year-old will step up multiple divisions to face former British and Commonwealth champion Williams in the Granite City.
Williams famously stopped former undisputed heavyweight world champion Tyson in the fourth round of their Louisville, USA, clash in 2004.
At short notice McAllister stepped up to fight at heavyweight in April, defeating Lee Kellett 39-37 in Ayr.