Ulster and Saracens will be playing for a home semi-final when they meet in the Heineken Cup quarter-finals.
The victors will host the winners of the last-eight tie between Clermont and Leicester.
The other semi-final could be an all-Irish affair with the winner of Toulon v Leinster hosting the winner of Munster v Toulouse.
The quarter-finals take place from 4-6 April with the semis following on 25-27 April.
Ulster and Saracens met in the last eight last season, with the Londoners the hosts on that occasion and running out 27-16 winners.
The last eight includes six past champions, with Saracens and last year's beaten finalists Clermont the only survivors this season not to have won the tournament.