Remarkably, tonight's quarter-final in Stradey Park marks the first Heineken European Cup meeting of the Welsh and Irish standard-bearers in the competition.
And it is in this setting that two Kiwis, one of whom was a boyhood idol of the other, could play a pivotal role in what is only the second time they have played against each other.
Regan King is widely seen as the primary running threat to Munster's hold on the cup, a gifted midfield ball-carrier who was nominated on Planet Rugby's World XV before Christmas, despite being the only player on that selection not currently playing Test rugby.
There was a time, circa 1996 to 2002, when Christian Cullen would have walked onto such notional selections. Still the leading All Blacks try scorer of all time, with a stunning 46 tries in 58 Tests, Cullen was undoubtedly the most gifted attacking fullback on the planet for a few years, and perhaps even of all time.
He had a truly innate nose for when to time his runs and for the line, astonishing strength for one so slight and blinding pace. It's curious to think that his abilities at Test level were perhaps not fully utilised by the All Blacks, John Hart sacrificing Cullen's ability to hit the line by converting him into an outside centre in the World Cup year of 1999, before John Mitchell prematurely jettisoned Cullen and other established All Blacks prior to the 2003 World Cup campaign.
King has no doubts where Cullen ranks. "He's right up there as one of the best players New Zealand has ever produced. When I came through my age group rugby he was my idol. He was the best fullback in the world in his prime. He had blistering pace and pound for pound he was one of the most powerful players in New Zealand. He would be my number one fullback. It was the way he would hit the line that made him so special and he was the second strongest players in the Wellington squad."
Cullen, now 31, was in his pomp on his first appearance at Stradey Park, as part of an all-conquering All Blacks team that went unbeaten in 1997, their only blemish being a draw with England in the final game of their European tour that year. In the tour opener Cullen scored four tries against Llanelli at Stradey Park in an 81-3 victory which marked the 25th anniversary of the Scarlets' victory over the All Blacks. Stephen Jones played at centre for Llanelli that night.
Along with Cullen, King was part of the All Blacks' squad that toured Europe in 2002 when winning his only cap against Wales in Cardiff, but they never played together. Their only previous meeting was in an NPC game when Waikato played Wellington.
It was Cullen's and Munster's misfortune that he damaged his shoulder in an NPC semi-final in 2003 in his last match for Wellington, so delaying his debut until the following February and also triggering an unfortunate sequence of injuries which have lessened his impact with the province.
Yet rather than take up more lucrative offers in France, a sense of wanting to show Munster his true worth saw Cullen remain for a fourth season. Ironically, the opportunity tonight's game presents him is due to Shaun Payne's injury-enforced absence and he will be desperate to avail of it.
"You never lose your instinct for the game," maintains King, at 26 five years Cullen's junior. "I'm not sure if his body can still do the things it used to be able to do for him but even at 75 per cent he's still a great player and we'll have to keep a pretty close eye on him."
King singled out Halstead as "the go-to player for Munster nine times out of ten" and even with their injury woes the Llanelli centre is fully cognisant of the quality in the champions' ranks. "Munster are probably a little bit more forward orientated. They're very passionate and never know when to give up. Even if we go ahead we simply won't be able to ease off."
King admits his sense of anticipation has never been so acute for one game this season.
"We've all been looking forward to this clash ever since we qualified in January. It's going to be a real step up in pace and intensity. Every game from here on in is going to be a cup final. We've got the holders coming to us and we know they won't be giving up their title without a fight."
