Eddie Hearn, promoter for IBF, IBO, WBA, WBO heavyweight champion Anthony Joshua, says the negotiations are going forward for a potential 2021 two-fight unification series with WBC champion Tyson Fury.
Earlier this month, it was revealed that both sides had agreed to certain financial aspects of the deal - where the first bout would have a 50-50 split and the rematch would be a 60-40 split in the initial winner's favor.
Hearn believes the first match could possibly land in the summer of 2021.
Both boxers have contracted assignments lined up.
Fury has to make a defense against Deontay Wilder in a trilogy fight, while Joshua has to make a mandatory defense against the IBF's top man, Kubrat Pulev.
Should both champions win, they have to sort out some of their other mandated items - with Fury owing a mandatory defense to Dillian Whyte and Joshua having to contend with a WBO mandatory obligation to Oleksandr Usyk.
Despite all of the roadblocks, Hearn feels confident the two fight series could come off.
"The bulk is done, the financial elements of the deal," Hearn told Sky Sports.
"There is always stuff that is out of our control, ie the fighters winning their next fights. [Fury's US promoter Bob Arum and I] had a good chat [on Thursday]. We're getting along alright. We have our words backwards and forwards but we both want to make the biggest fight of all time.
"He's made many of them in the past and I want to make one that goes down in history as well. We're all moving forward. We talked about the site, the other elements of the deal and we agreed to move forwards by papering this. Dotting the i's and crossing the t's. Get this boxed in for 2021."
As far as the location, the UK would make the most sense - but there numerous locations likely to outbid every British venue.
"Everybody knows, including AJ and Fury, we would love this to take place in the UK. It's two Brits fighting for the undisputed championship. But there is so much interest from around the world that I do believe one of these fights will take place outside of the UK," Hearn said.
"I'm happy to do one in the UK, one outside. But I'd be disappointed if we couldn't do one in the UK. The fighters and their close teams will make a collective decision. While I want it in the UK, I just want the fight. I want to see AJ become undisputed heavyweight champion of the world."