For current European champions, Munster, it will be their eighth semi-final appearance in ten years, whilst their opponents in the mouth watering all-Ireland tie, Leinster, make it to this stage for the fourth time, although they have never lifted the trophy.
Cardiff Blues, who next week face Gloucester in the Anglo-Welsh EDF Energy Cup at Twickenham, reached the semi finals for the first time since the region was formed with a 9-6 victory over French aces Touluse, however their forerunners, Cardiff, played in the very first Heineken Cup final at the Arms Park.
Director of Celtic Rugby, David Jordan said "Congratulations must go to all the teams for their performance over the weekend, a clear reflection of the success that Magners League teams, and their players now enjoy when they transcend into other tournaments.
"With the RBS Six Nations Trophy once more safely secured in Celtic hands, there is now all to play for to ensure that the Heineken and EDF Energy Cups will both be retained by Magners League teams. Good luck to all those taking part."