Carl Froch will defend his IBF and WBA super middleweight titles against George Groves this winter.
The all-British clash will take place in late November or early December, with a venue to be confirmed at a later date.
Froch added the WBA title to his IBF belt when he defeated Mikkel Kessler in a thrilling rematch at the O2 Arena in May, with unbeaten Groves capturing the vacant WBA Inter-Continental title on the same bill with a fifth-round stoppage of Noe Gonzalez Alcoba.
Groves was named as the mandatory challenger by the IBF and Froch believes it is a fight that will capture the imagination of British sports fans.
"I'm excited the first defence of both my belts is a big domestic clash," said Froch. "I am a proper fighter and a proper champion and I will always face my mandatory challenger rather than vacate the title.
"I've known George for a while, I've sparred with him and watched him grow and now he's my mandatory. I will be pouring everything into my preparation for the fight and George will face the very best of me."
Groves added: "This is the biggest fight of my career and being a world champion is something that I dreamed of as a kid. I'm well ranked across all the governing bodies but fighting Carl is the one that I wanted the most.
"He is a big name in the UK and a well-respected champion around the world, and I have a great team around me that can put together the right game plan to beat him and become a world champion and a major force in the super middleweight division."
Promoter Eddie Hearn says fans can expect an exciting night of boxing with a packed undercard when full details of the fight are released.
"I'm delighted to have got this fight made," said promoter Eddie Hearn. "It's a great fight for British boxing with a real throwback feel to the big domestic fights in the super middleweight fights in the 90s.
"When George became the mandatory challenger, I knew there was no way Carl would relinquish the belt and no way that George would look anywhere else."
Froch vs Groves most likely outcome
Froch destroys an overmatched Groves
Froch battles to a points win
Groves becomes first to stop Froch
Groves shows class to win on points