The self-confessed reality television junkie, said he felt like he was living in a dream.
He wants to share what he has learnt during his career. "It's about sharing tips and tricks that I taught myself throughout my career."
His role as vocal coach will include helping contestants choose the right song to sing.
"It's a position which comes with a lot of responsibility. My aim is to bring out the absolute best in every single act so we can create the next super star or super stars."
Meanwhile, Merito was amazed by the level of interest in a YouTube clip which went viral of him, Stan Walker and others singing Unchained Melody in a kitchen in Australia. The clip has attracted more than 18,000 likes and 10,000 shares on Facebook.
"I feel honoured and humbled so many people enjoyed it. It was literally thrown together at the last minute for our spiritual mum who has been diagnosed with pancreatic cancer. We were sitting on the couch, nek minute Stan said - 'Let's record it'."
Merito said the popularity of the clip was "testament to how much we sang from our hearts for our Aunty Audrey Phillips".
The X Factor NZ publicist Chris Henry has confirmed viewers will see a few Rotorua people on the first episode which screens on Sunday, April 21. "The producers were thrilled with the level of talent that came out of our Rotorua auditions and we can confirm you will see a few local stars come the first episode," Mr Henry said.
To view the video of Merito, Walker and others singing Unchained Melody visit our website or scan the QR code: 100413stan