Le Stadium will host Toulouse's mouthwatering Pool Two showdown with one of their greatest rivals on the European stage.
Between them the clubs have claimed six Heineken Cup titles, Leicester winning two, and both are desperate to gain a critical early foothold in the group phase.
Leicester are well versed in what to expect when they visit the French rugby stronghold, and Tigers star Allen stresses the importance of matching Toulouse's intensity.
"It's always a hostile atmosphere when you play in France in front of their big home crowds, but that will give us a great buzz to be part of and we will try and silence them," he said.
"The Heineken Cup is the next step down from international rugby, and for those who have not played Test rugby it is the next best thing to progress your career and put a marker down.
"We are looking for a good performance and, although we are coming off the back a pretty good run in the Premiership, this is another step up.
"Toulouse are a quality outfit and it is massively important we give a good performance. We have to hit the ground running and get it right.
"If we lose and don't take anything from the game and they get a bonus point win, then we will be playing catch up down the line so we want to try and get as much out of it as we can."
Flanker Steve Mafi and full-back Scott Hamilton start after recovering from injury, while prop Marcos Ayerza features on the bench for the first time after completing Argentina duty.
Toulouse head coach Guy Noves, who has selected centre Yannick Jauzion on the bench pending a fitness test, is braced for a mighty battle.
"Leicester have been European champions and champions of England and have experience at least equal to our own," he said.
"This will be a match of the highest level, the one everyone has been waiting for since the start of the season."
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