The Welsh singing legend was a coach on the show for its first four series but was cut from the line up in 2015 for the then upcoming 2016 run.
The fifth series last year was the least watched to date and was down around 2 million viewers on the previous year.
An average audience of 6.5 million tuned in to 2016's show compared to the 8.5 million who watched in 2015 when Sir Tom was on the panel.
Speaking ahead of his return to the show now it's on ITV, Sir Tom didn't hide his glee over how ratings declined without him.
"It took a dive afterwards," Sir Tom said of the show after his exit. "They were losing viewers, and I thought, 'well, that's OK!' He he he! I think they lost two million viewers. "
Speaking to Radio Times magazine, Sir Tom said the biggest upset came from his late wife, Linda, who tragically passed away last year.
"When my wife heard I wasn't doing it, she said, 'So you don't want to do The Voice any more?' I said 'It's not my decision' She said 'You must be joking!'" Sir Tom explained. "God bless her, she passed away before I was asked to come back.
"She would like the fact that I'm doing the show now."
Sir Tom Jones will be reunited with Will.i.am on The Voice UK panel this year with the pair joined by new coaches Gavin Rossdale and Jennifer Hudson.
The Voice UK 2017 launches this Saturday night on ITV from 8PM with the first round of blind auditions.