In doing so he will realise a dream.
"It's awesome," said Pettybourne.
"It's a privilege and an honour to represent our families, our culture and our heritage.
"It's something that I've been looking forward to for a while.
"It's an honour and I'm ready for a big game on Saturday."
Pettybourne can't wait to take the field against traditional rivals Tonga in a game expected to continue the tradition of fiery encounters between the two nations.
"It's a big one, it's always been a big one," said Pettybourne.
"It's going to be my first one against Tonga.
"It'll be a pretty tough game, pretty physical."
The Samoan set up has come a long way since the Rugby League World Cup in 2008, with the likes of Nigel Vagana and Roy Asotasi working hard to make it viable for young Samoans to represent their culture.
"They've been encouraging this for years," said Pettybourne. "It's awesome to be involved.
"Learning from the experienced guys is something I'll take on board and hopefully be able to share with the boys at Wests Tigers."