Talks are under way to secure a venue, with Wembley, Old Trafford and the Emirates Stadium among the possibilities.
The bitter rivals met in Manchester in November with Froch's IBF and WBA super-middleweight titles on the line. Froch prevailed when the contest was stopped in the ninth round but Groves successfully appealed to the IBF, who ordered a rematch.
Hearn, the Matchroom promoter, said: "We're in discussion with six or seven stadiums all over the country right now. They are huge stadiums because this is a huge event.
"We're looking at a crowd of up to 80,000 for this fight. We have had discussions with Old Trafford, Wembley, the Emirates Stadium, the City Ground, Twickenham, Cardiff . . . it's a special fight.
"Over the next week we'll be closing off a deal with one of them. I believe this will be the biggest fight in British boxing history and I want to see how big we can make it because it appeals to everybody.
"It was difficult to arrange because there were two egos to deal with but it would be a travesty if it didn't happen. The fact is they don't like each other and they don't do a very good job of hiding that."
In a nerve-jangling first encounter, underdog Groves floored Froch in the opening round and had seized a scorecard lead when referee Howard Foster intervened as the resurgent Froch fired a barrage of shots.
Although the tide appeared to have turned against Groves, Foster's decision to step in was widely condemned as premature.
It was a spectacular fight that evoked memories of the great Nigel Benn-Chris Eubank-Michael Watson battles of the 1980s, but Froch was reluctant to grant the rematch. However, he said after yesterday's announcement: "I'm looking forward to shutting George Groves up once and for all and putting him behind me
"I've already beaten him, so I'm chilled and relaxed. He's going to get another pasting.
Groves said: "I'm really chuffed. I didn't think for one second that Carl Froch would take this fight. I systematically beat him from round one until round nine before the referee jumped in. He's on a hiding to nothing.'