O’Callaghan and company currently are well placed in Pool One following victories over Montauban and Sale Sharks and look set to reach the quarter-finals.

Munster emerged from a fiendishly-difficult group last season that included Clermont and 2007 European champions Wasps, so they will not be entering unknown territory.

Their task, though, has not been made any easier by an injury list that means they are without the likes of Rua Tipoki, Jerry Flannery and Denis Leamy this weekend.

O’Callaghan said: “Clermont will be looking to put one over on us for last season, when we effectively stopped them making the knockout stages.

“I have never played a game in France that wasn’t hugely demanding, and this one will be right up there with internationals in terms of speed, intensity and physicality.”

Clermont, who suffered a shock domestic defeat against French Championship strugglers Mont de Marsan last time out, welcome back international wing Aurelien Rougerie following a lengthy injury absence.