Harrison, 40, has not been in the ring since being comprehensively defeated by David Haye 15 months ago.
"I've never been more disappointed in myself as I felt that night. Anyone can lose, but I didn't lose with dignity, so I was never going to retire off that performance," said Harrison.
More recently, the former Olympic and European champion has taken part in the BBC's Strictly Come Dancing.
The proposed bout will take place on Saturday, April 14.