The Scarlets have run dry of the hottest tickets in Welsh rugby this season, but are keeping a reserve list for fans hoping the French side will return some of their allocation for the crunch European fixture on Friday 11 April.
Wales' leading lights in Europe since the competition began in 1996, Llanelli will be hoping for another famous night at Stradey Park with their first sell-out crowd of the season.
"It's no secret that these European matches are treated as the biggest games of our club season at Llanelli," said chief executive Stuart Gallacher.
"But they are also the biggest matches for the fans and they have tended to vote with their feet by filling Stradey Park when we have played the likes of London Wasps, Leicester Tigers and Cardiff in this competition over the years.
"We think we have the best fans in Wales and they have proved it once again by snapping up every ticket and hospitality package we had to offer. I don't doubt we would have been able to fill a ground twice the size of Stradey and more if we had the chance."