The Los Angeles-based McAuliffe, originally from Sydney, was glad to return home for the part when writer-director Holmes reached out to him a few months before shooting began. "I'm always grateful whenever someone extends a offer like that," he says, "and I've always wanted to shoot in the Aussie outback, which I've not done very much of.
"So this was one of those dream come true situations." In between horse riding and gunfights, McAuliffe says he did get a bit of teasing by his fellow castmates Jack Martin, Jamie Coffa and William Lee.
"I just went to the premiere in Forbes and Jack introduced me to people as Big Shot," McAuliffe says with a laugh. "So that was kind of funny. I love working with people that are my age or thereabouts, 10 years either side, because it's kind of like a summer camp."
McAuliffe began his career as a child actor on shows such as Packed to the Rafters before breaking through internationally in the 2010 Rob Reiner rom-com Flipped. That led to the 2011 sci-fi film I Am Number Four and the part of young Gatsby in Baz Luhrmann's 2013 epic The Great Gatsby.
Now at the age of 21, McAuliffe says, "They have me going in these days to audition for characters that are anything from 16 through 26. Someone told me the other day they thought I was 30. I don't know how I felt about that! I don't know whether to take that as a character compliment or an aesthetic offence."
To read an interview with McAuliffe's co-star Jack Martin, who plays Ben Hall, pick up this week's WHO on newsstands now.