Cullen has Springbok World Cup winner Jacques Nienaber on his staff this season and cites the South African's new defensive system as one major change.

He added: "We've made some pretty drastic changes from last year, in particular with regards to how we defend.

"Delivering that kind of defensive performance on a big day against a really good attacking team, that is probably number one on the agenda this week.

"Our game is completely different to what it would have been this time last year.

"It's two good teams, two strong traditions in the competition. Hopefully it'll be a great contest."

No player who started the semi-final victory over Northampton for Leinster also started the loss to Ulster in Belfast, a defeat that saw them drop to third in the URC, but Cullen was able to give valuable minutes to Irish internationals James Ryan and Hugo Keenan on their returns from injury.

Toulouse also rotated heavily in their last league game before the final, beating relegation-threatened Montpellier in the Top 14, and Cullen defended the selection policy despite a 23-21 derby defeat that could see them have to travel in the later rounds of the URC play-offs.

"I think everyone understands that, don't they?" he said.

"In terms of the prep for some other guys, [it's] trying to get a step ahead, a bit of mental freshness even coming into the week. But we've some guys here that obviously will be featuring [against Toulouse].

"There's lots of things that go into it. It's not exact but in knockout games you need to do everything you can to set up your team as best you can to give you the best chance of winning the game. Hopefully we'll see a big performance.

"Everyone is just excited by the prospect now.

"We've had amazing support all year and hopefully in London we'll have a big Leinster following and make it a special day.

"We need to work hard this week and get excited by the challenge."

Although he has played just 24 minutes since the end of the Champions Cup pool stages in January, Leinster remain hopeful that Garry Ringrose could play some part against Toulouse.

"There's going to be some tough decisions this week," added Cullen.

"We'll see how everyone pulls through, make some calls and hopefully we'll come up with a strong group of 23 that will represent the wider group, the club and the fans well. It'll be a great occasion."