Ireland v Australia International debutant: Andrew Trimble dares to be different but not in a superficial way. The chiselled appearance - he's nicknamed Arnie - suggests a traditional rugby prototype but he is far from the stereotypical player.

On Saturday at Lansdowne Road he'll make his debut for Ireland in the Test against Australia less than a month past his 21st birthday.

While others may look forward to the trappings of this success, Trimble casts his eye in a different direction. Christianity is very important to him and it's not just lip service to his Theology studies at the Bible College in Dunmurry.

He is devoted in deed as well as word. It was that missionary zeal that took him to South Africa in the summer, less than a week after representing his country at the Under-21 World Cup in Argentina.

Exodus, an organisation based in Portstewart, arranged an "outreach" programme to townships like Temblethu, just outside George in the Eastern Cape. Trimble explained the process as a method of introducing Christianity through sport.

"It was in secondary school that I really began to take my Christianity seriously," he said. "I learnt how special it is and how amazing it is to have a relationship with God as my best friend.

"Every morning I sit down and pray and read my bible and God teaches me something new. It's so much more exciting than not having God in my life. There's so much more purpose to what I do. It's a free gift and God's offered it to everybody.

"I'd been to townships in Kwa Zulu Natal the previous year. We worked mainly at a juvenile detention centre, where there were kids awaiting trial.

"Some of them had been convicted of rape and murder but they were amazing, and they were just so keen to play rugby. There were maybe 13 of us, and around 300 of them.

"We'd play rugby with them and then share our faith with them, morning until the sun went down. It was absolutely knackering but it was great. Because they had so little, they just appreciated everything you did for them. Resources were a bit thin on the ground."

Trimble is blessed with a sense of humour and retains a perspective about his chosen sporting profession.

"Obviously, it's hard to fulfil Christian ideals on a rugby pitch. There's gamesmanship and you lose the rag every now and again.

"You play as competitively as you can but it's difficult. I'm human and I'm going to let God down occasionally but he's just waiting there to say it's alright and put his arm around me."

His values shouldn't distract from tremendous athletic ability. From the moment he took to the playing fields of Coleraine Academical Institution this quality has been evident, manifest in playing for Ulster and Ireland Schools and Ireland Under-21s.

This season Ulster coach Mark McCall gave him an opportunity, initially on the wing but then in his preferred position of centre, following an injury to Paul Steinmetz.

Trimble has been superb, and goals set at the beginning of the season have already been discarded as he reaches one after another.

"Some of the goals that I set for myself at the start of the season I've achieved them earlier than expected.

"It's certainly taken me by surprise as I didn't expect to get a cap against Australia or this early having only made my debut for Ulster a couple of months ago.

"I'm relishing the opportunity and looking forward to making the most of it."

Far from being fazed by those around him - he's never met the injured Brian O'Driscoll - he is enjoying every minute.

"I haven't played with Gordon (D' Arcy) before but in training I'm loving every minute of it. It's a great experience to play with players inside of me like Gordon and outside like Geordan Murphy.

"There's an awful lot of quality in the back line and the team as a whole.

"Thirteen is my preferred position and where I play my best rugby."

So was O'Driscoll a hero of sorts?

"I think Brian O'Driscoll was the hero for every young outside centre coming through in Ireland."

Modest and quiet off the pitch, he'll be impossible to miss on it.