In the 27-year history of the UFC, only seven fighters have won championships in multiple weight classes -- and only four of those have held both titles simultaneously.

Such is the rare air UFC middleweight champion Israel Adesanya (20-0) is hoping to reach Saturday, when he challenges Jan Blachowicz (27-8) for the light heavyweight title at UFC 259. The Nigerian-born, New Zealand-based star will look to become the UFC's next ''champ-champ,'' a term used by Conor McGregor in 2016 when he became the first to hold two belts at the same time.

The feat was so unusual that UFC president Dana White didn't have two championship belts ready for McGregor's postfight photo-op in the Octagon after he beat Eddie Alvarez for the lightweight title. White thought McGregor would have brought the featherweight belt he already owned. As McGregor yelled in the Octagon for a second strap, someone from the UFC borrowed the welterweight belt of Tyron Woodley, who had fought in the co-main event. That set up the iconic shot of McGregor sitting on top of the cage in Madison Square Garden, holding up two trophies.

"Winning them both at the same damn time was the best," McGregor posted on Instagram in 2019. "I've had glorious moments in my career, but to be able to strap both unified world titles around your waist with no question, no doubts as to who is the champion, that was the most glorious moment of my career -- winning them both at the same time and birthing the champ-champ."

Ruling two divisions at the same time was a career-changing moment for each of the four champ-champs. Daniel Cormier, Amanda Nunes and Henry Cejudo discussed how the accomplishment changed their lives, touching on everything from finances to national pride. And their advice to Adesanya ranged from "be careful of the power" in the heavier division to be ready for your life to change.

Editor's note: Some content was edited for brevity and clarity.

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'It really does change everything'

By Daniel Cormier

Cormier was the light heavyweight champ from May 23, 2015, until Dec. 28, 2018. And he was the heavyweight champion from July 7, 2018, until Aug. 17, 2019. Cormier did not defend the light heavyweight title after winning the heavyweight belt.

It was never my idea to go for a second belt. It was Dana White's. He came up to me in Boston, right after I defended my light heavyweight belt against Volkan Oezdemir in January 2018, and that was the moment I realized I was getting a chance to chase history. He came in the back and said, "What do you think of you versus Stipe Miocic for the heavyweight title?" And I was like, "Wait, what?" And after a minute, I was all in. He said, "Let me work on it." That was Saturday. I'd barely gotten back to San Jose (California), and he called and said, "You and Stipe as coaches on The Ultimate Fighter, then fight for the belt." I think I said yes to everything by Monday. It was crazy.

The beauty for me going into that Stipe fight was that he wasn't a big guy. I was able to go fight a guy that weighed 241 pounds, that's only a 15- to 20-pound difference from what I was weighing at light heavyweight. I didn't fight a guy who weighed 260 pounds.

When I think about those two title victories, I can honestly say I felt I was supposed to win those fights. I knew Stipe was tough, and I knew it was going to be hard to beat him, but I just felt like I was supposed to beat him at the time. I felt the same with Anthony Johnson for the light heavyweight title.

When you become a UFC champion for the first time, it's such a big deal. All we want as fighters is to become a UFC champ. So, to get that first belt, it was so satisfying. But I knew very well what becoming the heavyweight champion meant. The moment I won the second belt and became the heavyweight champ, my profile raised instantly. When you're the heavyweight champ of the world, people take notice. It was different overnight.

My pay structure changed when I moved up to fight Stipe, and then once I had both belts, it never went back down. My pay never changed, even when I lost the title back to Stipe and then I challenged him again. It only got bigger from the moment I moved up. Once you get two belts, it really does change everything. So, what Adesanya is on the cusp of right now, if he wins the second belt, he's going to see a change overnight.

It takes a perfect storm to be able to do this. Every person who has been a double-champ, there were so many things that could have prevented it. Look at Conor McGregor. Khabib Nurmagomedov was always hurt when McGregor went to lightweight and won a second belt. Imagine if Khabib had been healthy. Conor probably never wins a second title. So, I look back and think, what if it wasn't Stipe for me, a guy who I felt I matched up well with? If it had been Francis Ngannou, would I have still moved up or decided he was just too big and stayed at 205 pounds? I don't know if I would have made the same decision.

I think for Adesanya, he understands what's in front of him. And that's part of the reason it's happening right now. He's not fighting a wrestler, a guy who is going to try to take him down the whole time. He's fighting someone who will stand in front of him. I wonder if he were facing a different style, like when I was champion and taking people down, would he still be doing it? And I'm not trying to say I could beat Adesanya, I'm just pointing out it's a completely different style. Here, he gets to fight for a second belt with an opponent who will meet him on his terms.

I would encourage Adesanya to pay close attention to everything that is going to come in his direction. Be prepared to be bigger than you even could have expected. Once you get two belts wrapped around you, that image lasts a lifetime. Me sitting on top of the Octagon with two belts, Conor having them over his shoulders, those things never disappear. It's not only the MMA world paying attention anymore, it's the entire sports world.

'I see myself and my moments in him right now'

By Amanda Nunes

Nunes won the bantamweight title on July 9, 2016, and won the featherweight title on Dec. 29, 2018. She has defended her 135-pound title twice and her 145-pound crown once since becoming a champ-champ. She'll be defending at featherweight against Megan Anderson at UFC 259.

When I saw the 145-pound division had nobody there but Cris Cyborg, I started to think about me and her. And I thought about Brazil, how it would be huge -- two dominant female fighters from Brazil. I thought about putting the name of the country out there, as having the two best female fighters on the planet. I thought that fight was the best thing for me, for her and for all the girls out there watching. I felt like it would be huge, and said, "I want to do this. I have to do this, to make the women's division exciting." And at that point, I had already kind of cleared out 135 and I wanted to challenge myself. And when I thought about a challenge, I thought about Cyborg.

I think I always knew inside my heart and mind that I would be the one to beat her. I was just waiting for the right moment. But, you know, who woke that up inside of me was [wife and UFC strawweight] Nina [Ansaroff]. We watched Cyborg beat Leslie Smith in 2016. I remember watching that fight sitting down, and after she won, Nina looked at me and was like, "You're going to be the one who will beat her." That was the moment everything started to build. From then on, I always knew, but I hid it. My coach said the same thing. Everybody in the gym said, "What are you waiting for? Let's do it." I believed in myself, but to have people believing in me even more than I did, I started to think, "I'm powerful for sure."

I feel like my two title fights at 135 and 145 played out very different than I actually thought they would. The most difficult part was the preparation for those fights. Before Miesha Tate in 2016, there were still a lot of things I needed to fix and get better at. I got the opportunity to fight for the title, but at that moment I wasn't sure if I was 100 percent ready. So, the preparations were harder than the fight itself. The biggest fight for me was actually beating Felicia Spencer last June, because at that moment I did something nobody had ever done, which was defend both belts as I held them at the same time. So, that was huge.

Israel is a champion, so he thinks like a champion. I think he's in a good spot right now. He has all the tools to beat this guy. I don't have any advice for him because I feel he's in the right moment. I see myself and my moments in him right now. I feel he can get it. I could be wrong, because we all know how MMA is, but I feel he's in a good place in his career.

'I would just be careful of the power'

By Henry Cejudo

Cejudo was the flyweight champ from Aug. 4, 2018 until Feb. 29, 2020. And he was the bantamweight champ from June 8, 2019 until May 24, 2020. Cejudo never defended the flyweight belt after becoming a champ-champ.

For me, I had to win that first one. You always have it in your mind what you want to accomplish, but I didn't see it into existence until I beat Demetrious Johnson in 2018. My honest goal was always to be the greatest combat athlete of all time. Not even the best fighter, or the pound-for-pound greatest, but to go down in sports as someone who did something no one else had done. But I didn't start believing it was going to happen until I got past Johnson. After that, I was an Olympic champ and a UFC champ -- so going for a second belt, that put me on GOAT mountain.

The more competitive title fight for me was Demetrious Johnson, the harder fight was against Marlon Moraes for the bantamweight title. One of them was a fight, the other was a competition. What I mean by that is the way I beat Demetrious was control, managing time, getting on top of him, pressing him in the final 10 seconds of the round. There was a lot of acting involved in that s---. I knew I had to show the judges that he was the man going backward. I had to use every edge I could to get that win. People don't talk about that kind of stuff, but I'm a real one.

"I would just be careful of the power, because he's going up 20 pounds, and the power will change. The power changed for me, going up 10 pounds from flyweight to bantamweight. But I think he's gonna knock out Jan Blachowicz."

Henry Cejudo

I was struggling to make 125, and that became a burden. That's probably the reason I retired from wrestling too; the weight was too much. After winning my second belt at 135 and realizing I could stop a guy like Marlon -- that it's all about skill and belief and precision -- going up in weight isn't an issue anymore. That's why I feel so comfortable if I ever were to get the opportunity to go up to 145 pounds. I know I can become the first person to win a third belt, because of the confidence winning that 135 belt gave me.

Defending a belt is harder than winning another one, but more gold is more motivating. For me, right now, that's the only thing that would motivate me to fight again, is move up and fight for a third belt. And I know Dana knows I could win it, because he's mentioned he doesn't trust me to go out and win another one of his belts and retire again.

I do believe, with all sincerity, that among the champ-champs, the two people I beat -- I would put those credentials against any of the other double-champs. I will always feel like my champ-champ status was the greatest because I beat Demetrious Johnson. And when I went up a weight class, I was an underdog to beat Marlon.

I don't think you need to give Israel advice, because it's a great fight for him. I would just be careful of the power, because he's going up 20 pounds, and the power will change. The power changed for me, going up 10 pounds from flyweight to bantamweight. But I think he's gonna knock out Jan Blachowicz.