One of the fights boxing fans want to see most is a welterweight unification showdown between two-belt titlist Errol Spence Jr. and titleholder Terence Crawford, both among boxing’s pound-for-pound best.

The fighters also have said repeatedly in interviews that they also want to fight each other. And they have also said it directly to each other multiple times via phone or FaceTime.

“We talk and say how we gonna make this fight happen,” Spence told BoxingScene.com, estimating that he and Crawford have spoken on the phone or via FaceTime about four times.

“We basically go back and forth because I’m my own guy but I don’t handle my own business. So at the end of the day it’s boxing and we both got to get paid for it. I want to get paid for it.”

Both men want to be paid for what shapes up as their most dangerous fight and one that will mean a lot to their ultimate legacy in the sport. Complicating matters is that Spence is part of the Premier Boxing Champions stable, which is deep in the division, and Crawford is with Top Rank.

The outfits can work together even if it is rare. But they did collaborate on the Tyson Fury-Deontay Wilder heavyweight championship rematch that took place in February and they will do so again for the third fight between the big men that is could take place as soon as mid-December.

So even though Spence does not proclaim that he and Crawford are friends, they do talk about how to make their fight and how it would go.

“Not all the time but there are times we have done that,” he said of the two getting on the phone. “We’re rivals at the end of the day. We basically talk about fighting each other.”

Then Spence adds with a laugh, “He’ll say how he’s gonna kick my ass, things like that, and I say the same thing. He says he’s gonna f--- me up and stuff like that. But we both want (the fight) to happen.

“We have had discussions about the fight. He’s a cool dude. (The talk is) like in basketball. ‘You know what I’m gonna do to you, right?’ We just talking trash, boxing conversation. Just natural boxing jive conversation.”

While the fight perhaps looms it won’t be next. Spence (26-0, 21 KOs), 30, of DeSoto, Texas, is scheduled to defend his unified belts against former welterweight and junior welterweight titlist Danny Garcia (36-2, 21 KOs), 32, of Philadelphia, in the main event of a Fox PPV card on Nov. 21 at a venue to be determined.

The fight will be Spence’s first since he was in a serious car accident last October. He said soon after the accident, Crawford texted him to check in and wish him the best in his recovery.

“He’s not my friend but it’s basically like a respect,” Spence said of his relationship with Crawford.

Crawford (36-0, 27 KOs), 32, of Omaha, Nebraska, does not have a fight set yet but it is likely he will defend his belt against former world titlist Kell Brook (39-2, 27 KOs), 34, of England, on Nov. 14 on ESPN from the bubble of the conference center at the MGM Grand in Las Vegas.

Spence said he told Crawford that after he gets past Garcia and possible a rematch with Shawn Porter, whom he narrowly outpointed to unify belts last September, he can see the fight happening next year, although Spence also wants to fight legendary titleholder Manny Pacquiao.

“Then there’s nothing left on the table but Terence Crawford,” Spence said. “Who else would it be?

“I think it’s definitely gonna happen. I don’t know when but, hopefully, I feel like it can happen next year. This fight (with Crawford), I’m definitely going to push for it and Terence has been pushing for it too. Even when we talk on the phone or we FaceTime with each other we talk about it and say, ‘Man, it’s definitely gonna happen, but I got to get past the guys in front of me right now. But the fight is definitely gonna happen.’

“I don’t want to leave the division without fighting him because I don’t want that on my legacy -- people saying that’s the fight that never happened. Crawford is the most intriguing fight. That’s the legacy fight. I feel like that’s the biggest money fight out there for me too, so it would make sense for it to happen.”

Dan Rafael was ESPN.com's senior boxing writer for fifteen years, and covered the sport for five years at USA Today. He was the 2013 BWAA Nat Fleischer Award winner for excellence in boxing journalism.