WBF heavyweight champion Audley Harrison will face Poland's Tomasz Bonin on 19 June at Alexandra Palace.
Watch Harrison v Bonin live on BBC One at 2255 BST on 19 June
The Briton had tried to set up a clash with compatriot Matt Skelton for the British and Commonwealth belts.
But he has had to settle instead for Bonin, who is unbeaten in 26 fights and has hopes of springing a huge upset.
"Fighting Harrison was an opportunity I couldn't turn down," said Bonin. "My name will skyrocket after I take him out and destroy his future."
Harrison, meanwhile, said he looked forward to putting the first blemish on his opponent's record.
"I expect a tough fight as there is a lot at stake when two undefeated prospects fight and that usually means fireworks," said Harrison.
"But having completed my first 12 rounds last month against Julius Francis, I'm ready to bring the heat and send my fans home early with an explosive knockout."
On the undercard, Wayne "Pocket Rocket" McCullough takes on Ugandan John MacKay of Uganda in his first outing since his March 2003 loss to Scott Harrison.
"I can't wait to get back in the ring again. It has been a long time coming but I have kept myself fit and I am ready to step back in there."