A Junior Kiwi in 2011 and last year, Harris, was the Storm Under-20's "Young Gun," the equivalent of MVP in 2010, the same year he won the Ngati Kahungunu Junior Sportsman of the Year award.
The 194cm tall and 107kg Harris has told his family he is excited about the occasion and appreciative of his Dad's efforts in making the trip to the northern hemisphere. He also emailed a photo of him next to the Big Ben clock in London.
"Big Tohu next to Big Ben," proud sister Waimarie Harris said.
Tomorrow's debut comes a month after he announced his engagement to Melbourne-based Wellingtonian Natalie Jones.
Should Harris tick enough boxes tomorrow he will more than likely make his NRL debut against the Dragons in Melbourne on March 10. If that eventuates numerous members of the family will travel to the game and also to the July 28 clash against the Warriors in Auckland.
During his 1st XV days at Hastings Boys' High School, Harris provided plenty of hints he might one day crack the big time. Hawke's Bay league fans were left with no doubt he would during his final appearance for the Tamatea premiers before crossing the Tasman back in 2009.
Harris, who was 17 at the time, scored three tries and kicked two goals in a 54-12 drubbing of Phoenix at Kirkpatrick Park after earlier scoring four tries in the reserve grade curtainraiser, a 42-24 win against Bridge Pa. His former Tamatea premier league coach Adrian Rowlands was ecstatic when he heard Harris would be starting in the morning.
"What a buzz. Ever since Tohu was a young fella I've told his father we would be watching him in the NRL.
"It wasn't just his on-field skills but off the field he was zero maintenance ... no smoking, no drinking and no girlfriends for most of his teen years. Those three things might have changed now but he will still be looking after himself well off the field," Rowlands said.
Harris' cousin and former Tamatea premier club rugby coach Nui Bartlett said his selection for tomorrow's match is an appropriate reward for the work he has put in since linking up with the Storm.
"From what I've heard he has been training the house down in recent weeks. I still can't believe the Hawke's Bay Rugby Union weren't interested in him before he left the Bay.
"Tohu is about to play in a world club league final and the Magpies could do with a decent midfield back like he was in union before switching to the forwards for league," Bartlett said.
Storm football manager Frank Ponissi said Harris deserved his spot.
"He's probably one of the biggest players in our squad, outside of Jason Ryles, physically," Ponissi said.
"He's very quiet but he loves reading and is very respectful and quietly determined," Ponissi added.
That's how many of his former Hawke's Bay age group rugby teammates will remember him too.