On Saturday in Saudi Arabia, Artur Beterbiev and Dmitry Bivol will finally face each other in the ring.
Boxing fans have been waiting for the fight of the light heavyweight world champions for several years.
All four titles will be on the line in Riyad, where 39-year-old Beterbiev will hold the WBC, WBO and IBF belts, and 33-year-old Bivol will be the WBA (Super) champion.
Both men are undefeated and the contest is being promoted as a potential classic in the making.
Live text commentary for the main event and undercard, featuring the two Brits taking part in their world title fights, can be followed from 7pm BST on Saturday on the BBC Sport website and app.
Who will be the first undisputed light heavyweight champion in the four-belt era? Who will suffer the first defeat? Could a draw be on the cards?
BBC Sport asked the entire boxing world for their predictions.
Retired world champion and boxing trainer Anthony Crolla: “You can tell what a good fight it is because it's hard for so many people to pick a winner and I'm one of them. If I really have to, I just don't think Bivol will have the firepower to keep Beterbiev away. I see that Beterbiev will tire him out and maybe he will be able to stop the fight around the ninth or tenth round.
“But I also wouldn't be surprised if we saw a very disciplined performance from Bivol where he took down Beterbiev, punched him and moved him around, similar to what he did against Saul 'Canelo' Alvarez.”
WBC lightweight champion Skye Nicolson: “It's the typical brawler versus boxer and I have to support the boxer. It's hard for me to watch Bivol get caught in a situation he doesn't want to be in. He is so good at controlling the distance and pace of the fight.
“But if anyone can do it, it's Beterbiev. My heart says Bivol.”
Retired World Champion Barry Jones: “Beterbiev must be a slight favorite. He's knocked out boxers, he's knocked out boxers, and he can knock you out in the first or twelfth round. There is no round, no second, no minute in which you are truly safe with him.
“But I will still stick with Bivol. I just have a feeling that his intelligence, patience, discipline and calm approach may be enough to get him through the dangerous moments and help him make a close decision.
“Bivol may have to get off the floor a few times, but I think he could have the advantage early enough to sneak it home.”
British Heavyweight Champion Fabio Wardley: “I'm getting closer to Bivol, but it's probably one of the hardest fights to predict in boxing right now. This is a true pick 'em fight featuring two men with completely different styles. Beterbiev is a destroyer who can break through anyone. Bivol has great power, but he is such a pure and precise boxer.
“It's a matter of who can best impose their style on the evening and make an impact.”
Frazer Clarke heavyweight: “I keep changing my mind. I've been talking about Beterbiev all along, but now I think Bivol could handle it. But it’s a world-class 50/50.”
Retired World Champion Darren Barker: “I have Beterbiev as my favorite. When you have that kind of power, you knock people down with jabs. How can you not have him as a favorite? It's not huge, but it can turn off Bivol's lights at any time. But I'm betting on Bivol, unanimous decision, but a very close fight. I mean, the rounds will be enough for this fight, but I wouldn't bet on it.
Promotor Bivol, Eddie Hearn: “When you fight Beterbiev, it's like a ticking time bomb. The speed of this bomb depends on the opponent. Dmitry has the ability to really slow the ticking down. How slowly can he make it tick? The boom point is 12 rounds.
“Beterbiev will get you, but how fast can he get you and how much time do you have left before he gets you? The only person who can beat Beterbiev right now is Bivol.”
Former World Champion Hannah Rankin: “This is a brilliant clash of two fighters who have been waiting for a long time to fight, and now everything hangs in the balance.
“I'm going with Bivol on points because he's the younger and fresher of the two and his body is less worn out. However, it wouldn't surprise me if Beterbiev dumped Bivol during the fight.”
Saudi welterweight fighter Ziyad “Zizo” Almaayof: “Call me crazy, but I say Bivol is handling it very quickly. Beterbiev will always be in danger, but I see Bivol controlling the distance too well.”
Former world champion Regis Prograis: “I have to go for Bivol, he is a beast. This is a really good fight, the only downside is that they don't have big names for people outside of boxing fans. But this is a really bad fight.”
Retired world title challenger Paul Smith: “I said Beterbiev from the beginning and I think it might be a stoppage at the end of the match. I don't think there is anyone who can stop him. He's too stubborn.
“Bivol is obviously exceptionally good and has unbelievable footwork, so I wouldn't be surprised if he won. But I've always felt that Bivol, outside of the Saul “Canelo” Alvarez fight, has done enough to win fights and I'm not sure if that's enough against Beterbiev, I don't think he hits hard enough to earn Beterbiev's respect.
English cruiserweight champion Viddal Riley: “I'm betting on Bivol. He has better movement, better fluidity and will be able to fool Beterbiev in most rounds. However, in the later rounds, the situation will escalate into a war.”
