Eddie Hearn, promoter for IBF, WBA, IBO heavyweight champion Anthony Joshua (20-0, 20 KOs), says the likely showdown with WBO champion Joseph Parker (24-0, 18 KOs) is a major fight in the sport.
The discussions continue between Hearn and Parker's promoter, David Higgins of Duco Events.
As far as the date, March 31 has been tagged as grabbing the fight and Principality in Cardiff, Wales is being pushed as the frontrunner to host the contest.
Hearn views the contest as being a legacy fight for both of the undefeated boxers.
"Champions should be fighting champions, it's as simple as that. This is a very, very big fight. This is a legacy fight. Anthony wants to be the undisputed champion of the world, so this is a very important step to do that," Hearn said to Stuff.
"It's a unified title fight between two young, fast, dangerous, unbeaten heavyweight world champions, so to do it in an arena and not a stadium, I'd get lynched.
"It's my job and David Higgins' job to maximise the revenue for the fighters. My gut feeling is it will be outdoors in the UK."
Both promoters reached a deal on the revenue split last week, with Parker getting between 30-35% and Joshua gaining around 65-70% of the financial pot.
Joshua is coming off the biggest year of his career. He drew 90,000 to Wembley in London for his career-defining stoppage win over Wladimir Klitschko in April. And then in October, there were 78,000 in Principality to watch Joshua gain a stoppage win over a game Carlos Takam in the tenth round.
Parker did not exactly create shockwaves with his 2017 performances. He fought to a twelve round decision over Razvan Cojanu in a lackluster bout in May. And then in September, Parker came over to Manchester to win a twelve round decision over undefeated mandatory challenger Hughie Fury, in what many felt was another lackluster bout.
While Parker's last two fights lacked fireworks, a fight with Joshua will have plenty of action as both boxers are promising to win by knockout.
