"My wife [Tracie] saw an ad on TV for it and said I should go on it. I had a rather interesting audition via Skype and got through. We then went to Auckland to shoot the show."
So why Peter Jackson's Lord of the Rings trilogy?
"I'm a huge fan. We have a LOTR Trivial Pursuit at home and when we play I can't be in a team, I have to be by myself. Sometimes it's everybody else in one team against me, but despite that I still triumph," he said.
"I did use the game as part of my swot, but also I've seen all the movies, DVDs, extended DVDs, extras and virtually everything that's been put out including resource books put out by Weta Workshops, Peter Jackson's production notes. Yeah, I've got a fair bit of knowledge about them."
He said the shooting was a bit daunting and the pressure felt while under the spotlight can have an effect on your ability to recall things at times, but he felt he learned a lot from the experience.
"There's one question where those that know me well will probably end up giving me a swift kick. There are definitely strategies you can employ to help you play the game better, but I had a lot of fun. And I'll be appearing on TV so that's one more thing I can tick off my bucket list."
Mr Mitchell will watch the show at the house of a friend, who has set up a grandstand in his room to watch it in front of a large-screen television.
"Everybody I know says they think I'm a smart arse so this will prove if I am or not."
Peter Williams, one of New Zealand's most experienced and long-serving broadcasters, will take up a new role as the show's quiz master.
Contestants will once again face the unrelenting pressure of the spotlight and the black chair as they answer questions on their specialist subjects and test their general knowledge. And for the first time, the new series will add New Zealand knowledge questions to the challenge.
-Mastermind NZ is on at 7.45pm on TV One tomorrow.