The second-row, who is set to get married next weekend, acknowledges he faces an uphill battle to break the ever-present, and all-Munster, Paul O'Connell- Donncha O'Callaghan partnership in the boiler-house.
But Cullen is more than aware of the opportunity to catch Kidney's eye in Saturday's Thomond Park Grand Final between the two sides.
"I don't really try to think about it too much," Cullen told the Irish Daily Mirror.
"Obviously I would like to play a role in the World Cup - it would be brilliant. But there's quite a big distance to go between now and then, there's a big enough game this weekend.
"I try not to look too far ahead these days - I'm playing my final game of the season this week, getting marries the following week so that's plenty enough to focus on at the minute.
"I suppose any time you play it's a trial as such, but is it a 'final trial'? I don't think so.
"The coaches have so much information on us and it's a relatively small pool of players here in this country, certainly it's an opportunity for a lot of guys on the fringe.
"I suspect Deccie has a good 25 of his players picked, that's generally the way most coaches operate and it's always those final places.
"But then obviously there's a couple of internationals in August and other games thrown in there as well - so they're all trial games as such."
Despite being crown kings of Europe, Cullen doesn't expect a warm welcome at Thomond Park. He reckons Munster will provide a tougher challenge than Northampton Saints last weekend and that his side are the underdogs.
"They will go into this game as favourites, being at home and their preparations have been better," added Cullen.
"But we'll try and give a good account of ourselves when we get down there. We'll look at a few plays that we'll try and pull off against them.
"It's not ideal preparation over this week but you have to do what you have to do."
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