Riddick Bowe is back!!
We're told the 53-year-old former 2x heavyweight champion has inked a deal with Celebrity Boxing to fight October 23 in Miami.
Bowe -- who last fought to a unanimous decision victory in December 2008 -- does not yet have an opponent.
Back in his day, Riddick was one of the BADDEST dudes in the world. His pro record stands at 43-1 (33 KO's) ... with 1 of those big wins coming at the expense of the legendary Evander Holyfield.
Bowe is just the latest 50-something former champ to re-lace up the gloves.
Late last year, Mike Tyson and Roy Jones Jr. fought an exhibition match that ended in a draw.
Speaking of 55-year-old Iron Mike ... we're told Bowe actually has interest in fighting Tyson.
It's a fight boxing fans badly wanted back in the day, but the stars never aligned for Mike and Riddick.
We're told fight promoters are currently tracking down an opponent ... and an announcement will be made sometime over the next few weeks.