When Anthony Joshua first appears on the vast screens in Cardiff's Principality Stadium on Saturday evening, the roar of the crowd will pulsate around the venue; the closed roof leaves nowhere for decibels to escape.
Sat in one of the rows closest to the ring will be Joe Calzaghe, the man who finished his 15-year professional career with a 46-0 record. An involuntary smile will spread across his face, memories and nostalgia will engulf every pore and sinew; his thoughts will drift back to one November evening, 10 years ago, when he was the man at the centre of that stadium's attention, body reverberating to the roar of his adoring Welsh supporters.
The noise of the stadium will be is a far cry from the calmness of the Calzaghe Gym in Abercarn, where this interview with him takes place. Housed at the foot of slippery, awkward stone steps that he once sprinted up and down, the grass is a little longer than when Calzaghe trained here, the lights inside take longer to flicker on than before, but this is where he fine-tuned his art throughout an undefeated career that ended with him as undisputed world super-middleweight champion.
Enzo Calzaghe, Joe's father and trainer, walks along to greet us, opens the thick, awkward metal doors and shows us around. One room has been turned into a museum of Calzaghe's career -- the walls are covered with photographs and posters from his fights; boxing gloves are above the bar and in glass cabinets, as are portraits painted by fans, and a couple of sketches by Enzo. "No one can take these memories away from us," says Joe as he and Enzo walk around, reminiscing.
Enzo shows us the poster from Calzaghe's first professional fight and starts singing "from the Park to the Gardens", telling the story of his son's opening bout in Cardiff Arms Park to his final one in Madison Square Gardens against Roy Jones Jr.
Joe walks into the gym, navigating around the forever rotating bags hung from the ceiling; the ring lies empty, except for two punch mitts. He is carrying his five belts, with his son, also Joe, alongside him. There are no jabs at ghosts from days past, just a calmness of someone walking over a path well-trodden.
They moved into this gym in 2000; their old training base was "derelict and dangerous" so they set up home here, a mile or so from where he grew up in Newbridge. "This was our new home, it's a nice big place," Calzaghe says. "It was freezing cold in the winters, cold in the summers but as long as you're in your sweat suit, you're fine.
"This is our training camp, all you had to bring in were the sparring partners. Everyone knows me as Joe here, it's no big deal. I just do my usual runs, since I was 10 or 12 years old. All the fitness was from the mountains I ran up as a kid."
Calzaghe's teens were spent in the gym, sacrificing friendships and adolescent experiences to be the best fighter in the world. These thoughts were going through his mind when he was preparing in some quiet corner of the thundering Millennium Stadium. Now on the wall of the museum, in pride of place, is a vast poster advertising that fight.
The noise was overpowering that evening of Nov. 3, 2007, when Calzaghe fought Mikkel Kessler; the 50,000-strong crowd roared themselves hoarse with blind Welsh patriotism. But Calzaghe's tunnel vision, developed over 25 years of boxing to that point, kept him focused. His previous fight -- a comfortable victory over Peter Manfredo Jr. -- was also at the same stadium, but this occasion was on a different level. Calzaghe puts it on the podium of his most important, alongside victories earlier in his career over Jeff Lacy and Chris Eubank.
The Kessler fight -- one some felt he would lose against the younger, also undefeated Dane -- brought his career full circle. His first professional fight had been on the undercard of Lennox Lewis-Frank Bruno in the old Cardiff Arms Park in 1993. He returned 14 years later as the headline act inside the rebuilt venue, by then called the Millennium Stadium.
But it is only something that he could reflect on afterwards. The eventual joy that followed a unanimous decision stayed with him, but the renditions of Delilah and Bread of Heaven only slotted into his consciousness after the fight.
"You can feel the energy of the crowd but it was so big and vast in there that all I could see is that ring walk and then I look at the opponent when I'm in the ring and I see nothing else outside," Calzaghe tells ESPN. "When you're in there, you feel the energy of the crowd but you have to be completely focused.
"I haven't seen the ring walk [from that fight] for a long time. You can't see the atmosphere [as a fighter] - in the changing rooms, they tell you 'you have five minutes to go' so I'm doing pad work, keeping loose, I've got my earphones in trying to blank everything out and keep completely focused on the fight. You can't take in the fun aspect of the fight, the Welsh songs, but I'm just in my own world, my own zone."
Sacrifice, frustration and unwavering professionalism underpinned his victory. It was a rite of passage fight for him, a culmination of years of fighting -- metaphorically and literally -- to get deserved recognition for his ability, but coping with the pressure and adulation of his home support was essential.
"It's something within yourself and it's something which back as an amateur ... my first fight was when I was 10 and I lost. I was robbed. I went on to beat the same guy seven times afterwards.
"Over the years you just become stronger with what works mentally and there's a faith, a confidence in yourself.
"It's hard to take in - you're so focused on the fight, it's like a dream. You can feel the energy but you're in the zone and you can't take your eye off the ball for one second as you can get caught with a big punch from Kessler, which I did. So you have to get tuned back right in, use my boxing skills after five or six rounds.
"I am immensely proud years later to be talking to you guys and people reminiscing about the fight. That's all I wanted to do in boxing was to leave a legacy and memories on fighters -- with the Kessler fight, it wasn't just the occasion, but the fight lived up to the occasion and we did not disappoint."
Calzaghe is looking forward to seeing Joshua fight and fully expects him to see off Carlos Takam in a handful of rounds. But unlike that night against Kessler, this will be a visit to the stadium he can enjoy. He will be recognised by everyone there, but when the bell goes, he is looking forward to being in the shadows, albeit with memories of when this was his stage.
"It'll be nearly 10 years to the day, it'll nice to be there and listen to the atmosphere and think to myself, 'I did this once, last time it was here, and it was me...I once entertained here!'"