English champions Northampton and Heineken Cup runners-up Saracens have been handed tough European draws next season.
Saints, who beat Saracens in last month's Aviva Premiership final, will be in Pool Five of the new European Rugby Champions Cup alongside Racing Metro, Ospreys and Treviso.
Saracens, meanwhile, are in Pool One with Munster, Clermont Auvergne and Sale Sharks, which is arguably the hardest group.
Elsewhere, Harlequins are in Pool Two alongside Leinster, Castres and Wasps, while Leicester face last month's Heineken Cup winners Toulon, Ulster and Scarlets, with Bath in Pool Four, where they join Glasgow, Montpellier and Toulouse.
Saracens reached both the English and European finals last month, losing to Saints and Toulon, but they will have their work cut out to progress in Europe next term following Tuesday's draw in Neuchatel, Switzerland.
Toulon, minus the retired Jonny Wilkinson, will start as favourites in their pool, although trips to Leicester and Belfast have trouble written all over them.
And Bath, the 1998 Heineken Cup winners, must overcome a twin French heavyweight threat of four-time Heineken Cup champions Toulouse and Montpellier.
The five pool winners and three best runners-up will secure quarter-final places.
The draw has also been made for the second-tier European Rugby Challenge Cup, with newly-promoted Premiership club London Welsh grouped alongside Edinburgh, Bordeaux-Begles and Lyon.
London Irish, meanwhile, must get past Cardiff Blues and Grenoble, with Exeter facing Bayonne, among others, Newcastle meeting Stade Francais and Gloucester drawn alongside French pair Brive and Oyonnax.
The European Rugby Champions Cup succeeds the Heineken Cup, which ran for 19 seasons and ended in Cardiff 17 days ago.
After almost two years of negotiations, a new competition was forged in April comprising nine stakeholders - the six unions of competing teams, plus Premiership Rugby, France's Ligue Nationale de Rugby and Regional Rugby Wales - in addition to the Challenge Cup and a third qualifying tournament.