It's 20 years since Dubliner Alan Dunne was a wide-eyed young man, sharing an FA Cup final stage with Roy Keane and Cristiano Ronaldo.

Dunne was raised on stories of dad Paul playing on the same northside streets as future stars such as Liam Brady, Frank Stapleton and David O’Leary. He dreamed of being a professional footballer like his heroes.

And there he was, May 22, 2004, the Millennium Stadium in Cardiff, Manchester United versus Millwall.

“I was going to ask Roy Keane for his shirt, him being a fellow Irishman,” he recalls, “but I never had it in me in case he said no. So I didn’t ask him.

“But you got to see what the players were like, the likes of Ronaldo, Ruud van Nistelrooy, Roy Keane, Paul Scholes.

“You got to experience the build-up. Everything was brilliant. The semi-final (against Sunderland) was at Old Trafford, so you even got a taste of that.

“We qualified for Europe, so we got a two-legged game in that, which we lost in Hungary (to Ferencvaros).

“That was crazy, a crazy experience. They had flares, cages, you were getting darts thrown at you. It was one of the most hostile places I’ve ever been. Crazy place.

“They were passionate about their football. It was very hostile, but a great atmosphere. I was only a young kid then.”

Dunne was just 21 at the time and had only made a handful of first-team appearances for Millwall. To find himself on the bench for an FA Cup final against Manchester United was a dizzying high for the kid from Coolock.

“We all grew up playing on the streets in Dublin,” he says. “My dad played with Liam Brady many years ago.

“My dad played for Home Farm. He loves his football. Frank Stapleton, Liam Brady, David O’Leary; he played with a few of them. They used to muck about together.”

That Dunne has now spent more of his life in London than Dublin is evident when he speaks.

“The accent is gone, but I still call it home,” he says of the Fair City.

Twenty years later and he is preparing for another big final tomorrow. This time it’s a cross-London trip to Wembley, rather than the Millennium Stadium, which hosted FA Cup finals during Wembley’s redevelopment.

Bromley FC, a club from the east of London, not far from Millwall, are up against Solihull Moors in the National League Promotion Final.

A place in League Two is at stake. Bromley finished two places and five points ahead of Solihull over a gruelling 46-game season.

Dunne is assistant manager to Andy Woodman at Hayes Lane, having moved there from Leyton Orient as a player in 2017.

Anyone who has watched Welcome to Wrexham will know what an achievement it is to get out of the National League.

“It’s brutal. It is a brutal league,” he says. “There are a lot of ex-League clubs in there, big clubs that have been in the Football League for years.

“It would be nice for a town like Bromley, never been in the League, to get there.

“We’re a small club in this league, small budget, haven’t got the resources of most clubs, but we have a chance of getting into the EFL. It would be remarkable for the town.

“Last year we got to the semi-finals and lost out to Chesterfield in extra-time, so we wanted to go one better this year.

“Last Sunday we had Altrincham, the team that finished fourth, and we got the job done. Now we are one game from the English Football League and creating history for the club.”

In the 20 years between the 2004 FA Cup final and this weekend, he has visited Wembley as a player and a coach.

“I played there for Millwall in the FA Cup semi-final against Wigan with Millwall (in 2013),” he says. “They went on to beat Man City in the final. Then there were two play-off games.

“We were there for the FA Trophy two years ago. Then we had another FA Trophy when I was first-team coach. We got beaten in that.

“This will be my third time at Wembley with Bromley. I’m very lucky, very fortunate.”

He is seasoned enough now to know that tomorrow will mean very little if they don’t get the right result.

His experience of the huge stadium, which dwarfs Bromley’s 5,100 capacity ground, and it’s massive pitch could be one of those marginal gains that gives the Ravens an edge.

“The first time I played there, I think there were 60,000 or 70,000 at it. Millwall took the biggest following they’ve ever had there.

“It’s a great place, a great energy. But it can sap your energy, because it’s a big pitch.

“The occasion can really sap your energy if you allow it. Sometimes you can feel like you’ve played a full game after just an hour.

“I’ve had some good days and bad days there. It’s the pinnacle of English football to play there. Everyone wants to play there or coach there or manage there.”

Twenty years ago, 21-year-old Dunne was just happy to be there. The big occasion, the massive stadium, the bright lights.

“It was brilliant to be a part of it. We were never going to win, playing against United,” he says, “but no one ever gave Millwall a hope of reaching an FA Cup final.

“So to get an FA Cup final medal, to be a part of the day, was an incredible experience and I’m very proud of that.

“There are not many players who can say they’ve got an FA Cup final medal. It’s a runners-up medal, but it’s still a medal and a great achievement for Millwall.

“I was part of the occasion and the build-up and I was very fortunate.”

Tomorrow won’t be about the occasion. Bromley versus Solihull isn’t a David v Goliath story like Millwall and United two decades ago.

“Wembley is a good day out,” says Dunne, “but it’s only a good day out if you get the job done.”

Get the latest sports headlines straight to your inbox by signing up for free email alerts.