Triple European champions Toulon face a horror draw in the Champions Cup after being grouped with Bath, Leinster and Wasps.
Pool 5 will feature four teams with a total of nine European titles between them, including the three-time defending champions.
Leinster played all three teams in last year's tournament, topping their pool featuring Wasps, then knocking out Bath in the quarter-finals and losing to Toulon in the semis.
Elsewhere Pool 1 looks formidable, with four-time champions Toulouse joining English champions Saracens, as well as 1999 champions Ulster and first-time entrants Oyonnax.
Newly-crowned PRO12 champions Glasgow will go toe-to-toe with Northampton, Racing 92 and Scarlets in Pool 3. It will be a reunion for Saints and Racing, who were drawn together in last year's competition.
On their return to Europe's elite competition, French champions Stade Français face a pool packed with European pedigree after being drawn with Munster and Leicester, as well as Italian side Treviso in Pool 4.
And finally last year's beaten finalists Clermont will take on the Ospreys, Exeter and Bordeaux-Bègles in Pool 2.
Champions Cup Pools