While it was more work than he could have imagined, Merito said the rewards were much greater than he'd expected too.
"Every day I'm like it doesn't quite feel real, especially the last few months. Everything has just happened so fast."
Merito said working on the show was "crazy busy" but everyone was going the extra distance because they believed in the show and the talent.
The self-confessed reality television junkie said when he heard X Factor was coming to New Zealand he decided he had to get himself a part in it.
"I didn't even think I'd get an interview. It's a dream come true."
Expecting to be one of a group of coaches, Merito said discovering he was the only one was a bit of a shock.
"I thought there'd be maybe a couple of vocal coaches ... Nek minute I'm vocal coaching the whole 13."
Merito said he and the choreographer were like "the secret fifth mentors". While he went into the role thinking he wouldn't get attached, Merito said he couldn't help but form bonds with the contestants.
He said a lot of his work involved working with the coaches to get the best out of the contestants and he had to adapt his approach depending on the coach.
He describes Stan Walker, who he'll tour with later this year - as a "bro" and the future of New Zealand music. Merito and Walker will perform in his hometown Rotorua on the tour.
Merito said he was "super impressed" with Ruby Frost's music talent.
He'd always been a fan of Daniel Bedingfield's music but his personality was completely different than expected.
"I expected him to be real deep and quiet but he's the opposite. He's full on, a ball of life."
The judge he was most star-struck by Mel Blatt who he admits he had a crush on as a teen.
"I know she is a tough one but she is a beautiful person," Merito said.
He said he valued the friendship of the judges and other crew.
While he had spent the past seven years teaching singing, dancing and acting, mainly in Australia, Merito said it was a different experience coaching the contestants, some of whom hadn't had much experience on stage and in front of the television cameras.
"It's been really interesting being there for kids who aren't as confident or stage or screen savvy."
He said teaching and supporting the students had reminded him of his days at Lakes High and his old English teacher Denise Irwin, who would often stay behind to help him.
"She really went the extra mile for me and believed in me. I owe a lot to her," Merito said.
While the show wraps up with the grand final, Merito will stay on for an extra week or so helping the winner with the recording of their album. After a much-needed holiday he is straight into preparing for the tour with Stan Walker before working on Christmas in the Park.
