England have the largest representation with seven sides in the draw with title holders London Wasps seeded. France have six teams and their seedings will be decided after the French Championship Final.
Leinster are the seeded team for Ireland. Teams that are seeded from each country will be drawn into separate Pools as part of the Pool draw.
London Wasps (seeded)
ASM Clermont Auvergne /Stade Francais Paris *
Biarritz Olympique Pays Basque
Bourgoin *(French seeded team to be confirmed after the French Championship final being played on Saturday, 10 June)
Benetton Treviso (seeded)
Glasgow Warriors (seeded)
Newport Gwent Dragons