"They will still obviously be Sol3Mio shows. We want to keep that integrity.
"But I love Christmas and I want to create a memory for people, something families can come to and get that feeling of, 'Man, it's Christmas'.
"For me, it's about family and giving presents and going to church. I want to create that feeling through our music and our stories."
It's the perfect way to wrap up a year in which Mackay and the Pati brothers have travelled the world and sung for no less than the Queen at Royal Albert Hall in London.
"It didn't really hit us, that we were performing for the Queen, until we got on stage and we saw her.
"Then the three of us looked at each other and just gave a smile. Those are the things I will tell my kids about," says Mackay.
"Every day is a dream. What we are doing is such a surreal experience."
It's in stark contrast to life back at home where there's no high-rolling or special treatment.
"I'm still driving my Toyota Corolla. The same one I've been rolling in since the beginning of my time. And I'm not going to let him go. His name is Maximus and my car is the bomb.
"And, I do the lawns more than my brother at home and he lives there," he says, laughing.
When Mackay is back in New Zealand, he spends a lot of time answering fan mail and stopping to talk to people in the street. Some just want to say hi; others want advice on how to crack the big time.
"We don't have the answers to everything, even though we do have a book," he says with a grin. "All I can give to people is advice based on my experience. I relate it to something I've been through and I tell them my story.
"We like to remind people that it is possible. You can succeed."
Sol3Mio's Christmas-themed shows are at Black Barn Vineyards, Havelock North, December 19 and Villa Maria Winery, December 21. sol3mio.com