Charlie Clausen, whose casting as Zac was confirmed earlier this week, has given an insight into his character's personality in an interview with The West Australian.
"They were together back in the old uni days and Nat gets in touch when Casey goes to prison and asks Zac to keep an eye on him," Clausen revealed.
"The whole Brax, Nat thing, Zac is definitely coming in as that third point of a love triangle. It's my speciality to be honest; I've done quite a few shows where I get brought in as the third point of a love triangle."
Meanwhile, the actor and comedian set out his belief that Zac has "a lot of integrity" despite spending time in prison when he was younger.
"He's a really sort of stand-up guy but he's someone who's had a bit of a shady past and come through that so the benefit of that life experience is he's very non-judgmental, he feels like he can talk to anyone," he added.
The star praised co-star and on-screen rival Steve Peacocke, adding: "Steve's great. He's a very laconic, laid-back Dubbo guy. I'm always drawn to those kind of guys."
Watch Steve Peacocke, who plays Brax, talk about Zac's future to Digital Spy below: