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"It was the best experience of my life. It was massive, I couldn't believe the chemistry between all of us, it was so natural," Walker said.
Morrison said the crew of Mt Zion had become like a family.
"I just came to say hi to Stan, this is his whanau screening. We play father and son in the movie. We're actually like father and son, and the other guys in the movie. We're all very close. We had a wonderful time making the movie, we all helped each other out. The boys watched me and I gave them advice, although they didn't always take it," he said.
Morrison said the whole movie was "magic".
"It's a beautiful family film, it even surprised me. It went beyond expectations. It's making people's heart beat with pride as they walk out," he said.
"It's not just a film about a Maori family, it could be any New Zealand family, that Pakeha family down the road, the Indian family next door, anyone."
The first screenings of Mt Zion were held in Tauranga on Waitangi Day, with the eight showings between the Mount Maunganui and Tauranga almost all selling out.
Nationally, Mt Zion took $200,707 at the box office on opening day. Sony Pictures New Zealand general manager Andrew Cornwell said it was almost double the opening day of the previous biggest New Zealand hit movie, Boy, and second only to Sione's 2: Unfinished Business opening.
Mt Zion is a family-oriented story in which Walker's character Turei and his family are hard-working potato farm contractors in rural Pukekohe.
A talented musician, Turei dreams of his band, Small Axe, being the support act for Bob Marley's 1979 tour. But it's a dream that challenges the traditions and values of his upbringing and will set him at odds with his family, particularly his father (Morrison), a true man of the land.
Mt Zion is written and directed by Tearepa Kahi, who drew inspiration for the story from his own family background.