WBO cruiserweight champion Chris Billam-Smith will face Mateusz Masternak at the Bournemouth International Centre on Sunday, 10 December.
Poland’s Masternak, 36, has won 47 fights and lost five as a pro.
“Masternak is a superb fighter – he has proven that throughout his career,” Billam-Smith said.
“He’s got double the amount of fights that I have! He’s actually got more KO wins than I have fights, and his only losses are at the very top level.
“His style matches well with mine and I think it’s going to be a very exciting fight – I’m really looking forward to it.”
Billam-Smith will return to his home town, having dethroned former gym-mate Okolie at Bournemouth’s Vitality Stadium earlier this year.
The champion has also signed new long-term agreement with his Boxxerr promotions, with an obligation to contest a rematch with Londoner Okolie in 2024.
Masternak lost to Briton Tony Bellew in a European title bout at London’s O2 Arena in 2015 and says he is “looking forward to fighting in England again”.
He added: “I think Chris Billam-Smith is a very good boxer. He showed his warrior soul in his last fight and proved that he deserves to be champion. I have a lot of respect for him in that way, but I believe more in my skills and my experience.”