The Ulster pair, just two of the eight uncapped players on tour with the Niall O'Donovan-led Irish, are both just 23 and have come to the fore for their province in the last two seasons.

Lock McCullough is a former Ireland Under-21 captain and played 22 times for Ulster this past season, scoring one try. Wilson, a tigerish number 8, who scooped the Ulster Player of the Year award last year, lined out 18 times for Ulster in 2004/05, with an untimely ankle injury robbing him of a potential first Ireland cap against the US Eagles last November.

R.B.A.I-educated Wilson, who is set to carry on a proud family tradition as his grandfather Harry McKibbin and his two uncles, Harry Jnr and Alistair have represented Ireland at the highest level, said: "Training had gone really well for me during camp and it was a case of keeping the head down and working hard.

"When the team was read out it took a moment for it to sink in, but after the initial excitement the reality of the job at hand took over.

"The team all realise that a good performance will be required if we want to win on Sunday. My parents are travelling for the games, so it will be extra special for me to have them there to watch me win my first cap," he added.

A former cricket and golf schools champion, McCullough said: "Like Roger, I was delighted when I heard my name read out. The competition for places has been excellent and Niall (O'Donovan) has tried a couple of combinations during training, so I was delighted to get the nod.

"My focus now is to try and do a job to the best of my ability and hopefully contribute to a win on Sunday against a tough Japanese team."

Both McCullough and Wilson started in March's 15-9 win for Ireland 'A' over France 'A'. Four other starters from that Donnybrook game - Tommy Bowe, Anthony Horgan, Simon Best and Alan Quinlan - are included in O'Donovan's XV for Osaka this weekend.