With both sides now outsiders for the title, the game itself is something of a sideshow given the sense of expectation regarding Cullen.
However, both coaches see things in a different light. Munster's Alan Gaffney insists they can still retain the title in spite of last week's defeat by Llanelli Scarlets while his Ospreys counterpart Lyn Jones' ambition is to finish ahead of Cardiff Blues, thereby securing a place in next year's Heineken European Cup.
With the Blues virtually guaranteed at least four points from their clash with struggling Borders at the Arms Park tonight, Jones sees a win over Munster as crucial if they are to keep in step with their Welsh neighbours. And then there's the Christian Cullen element.
"We are delighted that he is making his Munster debut against us and our players are looking forward to coming up against him," Jones said.
"But he is just one of many fine players in their squad. At this level, it's all about pitting yourself against the best and it will not be easy. But we are improving and will be looking to build on recent performances. It's never easy away from home but we can take heart from the fact that other sides have gone to Munster and won."
Assistant Ospreys coach Sean Holly is clearly ebullient after last week'sdefeat of the Gwent Dragons although he also claimed "we are not surprised by that result as we are improving game by game. We were pleased to win but disappointed at not picking up a bonus point.
"For this game, we are bolstered by the return of Adam Jones at prop and winger Elvis Seveali'i. Both are refreshing additions and will help us to build on last week's performance."
Even though winger Shane Williams and flanker Jonathan Thomas are ruled out because of international duties and up to eight members of the squad are not available, the Ospreys include capped players in full-back Gavin Henson, scrum-half Andy Williams, hooker Barry Williams, prop Adam Jones, flanker Andy Lloyd and number eight James Bater.
Former Springbok winger Stefan Terblanche, who once scored four tries in the same game against Ireland; Tongan centre Dave Tieuti and Samoan winger Elvis Sevalai'i also line out.
Because of the "foreign player" rule, Simon Kerr is ruled out of the Munster squad. Frankie Roche starts at loose head prop having recovered from an eye injury and also there from the start will be Frankie Sheahan, Jim Williams, Anthony Horgan, JohnKelly, Rob Henderson, Shaun Payne and, of course, Cullen.
"Losing to Llanelli was a huge blow but it was always going to be a big challenge and we're still not out of it," Gaffney said.
"We have yet to play the sides ahead of us, apart from Llanelli, so we can still overtake them but I accept it will be very difficult."
: C. Cullen; S. Payne, J. Kelly, R. Henderson, A. Horgan; J. Holland, E. Reddan; F. Roche, F. Sheahan, G. McIlwham, T. Hogan, D. Pusey, S. Keogh, E. Halvey, J. Williams.
Replacements, from M. Lawler, J. Jones Hughes, C. O'Sullivan, F. Murphy; P. Malone, T. Hayes, J. Blancey, M. Cahill.
: G. Henson; S. Terblance, D. Tieuti, M. Brayley, E. Sevalai'i; S. Connor, A. Williams; A. Millward/C. Griffiths, B. Williams, A. Jones, A. Newman, L. Tait, J. Bater, S. Tandy, A. Lloyd.
Replacements, H. Bennett, Willward/Griffiths, R. Pugh, L. Bateman, G. Morris, R. Morgan, A. Durston.