The former Dublin milkman returns home with new club Toulouse to face Perpignan in next Saturday's all-French Heineken Cup final at Lansdowne Road.
And there promises to be as many of Big Trev's fans as there are travelling fans as Dublin prepares to welcome back one of their favourite sons.
"It's a dream come true for me to come home and play in a Heineken Cup final in Dublin - it has been one of the goals of my season," said former St Mary's College skipper Brennan.
"As soon as Lansdowne Road was picked to host the final it was Dublin all the way for me. Then as the competition went on, we were doing better and better and the chance of making that come true started looking more likely. Now we're on our way and I can't wait.
"Of course the game could go either way but I'm sure it will be an emotional day, especially if we win."
It is 18 months since Brennan last stepped out at Lansdowne Road for Ireland against Samoa having previously led St Mary's to AIL Final glory in 2000.
Asked if many of his friends and family will be making the short journey from his hometown of Leixlip to the capital next Saturday, Brennan joked: "About 5,000 of them".
He added: "It's not a big place but I think a few of the shops will be closing as there's a lot of people going to Dublin, certainly there are a lot of friends and family coming to watch the game.
"It's a pity there won't be many of Toulouse's hard-core fans won't be in Dublin, they just can't afford it. Not like the Munster fans who would have sold their car or their wife to get over for the semi-final in France. They made a big impression over here."
Known back home as the 'Barnhall Bruiser' for his abrasive but passionate game, Brennan made his debut for Leinster against the team he now plays for. The game typified everything that Brennan was about after being named man of the match despite getting his marching orders to the sin bin.
But Brennan has certainly settled in well to the laid-back lifestyle of the south of France after moving out with his family last summer.
"It was a big decision to come to a strange country with a different culture and different language. I came here not knowing what to expect or if I would even get a game but I'm really enjoying the new life and the rugby out here," he said.
"In fact I couldn't have asked this first year to go any better, I'm in the European Cup Final and the semi-final of the French Championship. It has been a fantastic experience and something completely new for me.
"Because of top players like Jean Bouilhou and Gregory Lamboley I've played half of my games in the second-row. But I've got used to it because the game here is a lot faster, it's all about keeping the ball alive, so there's not a big difference in the role of second-row and a flanker, only in the set-pieces.
"So even if we lose next Sunday, it will still have been a great season."
But for Brennan's fans there is only one way to wrap up such a fantastic season - and that would be with a place in the airplane to Australia for the World Cup in October.
"Of course I would love to go. It was disappointed not to be involved in the Six Nations but that's just one of those things. All I can do is get my head down for Toulouse and if it happens, it happens."