Series 10 of The Voice launched on Saturday night and featured an appearance from Stevie Wonder.
He appeared via video link with a special message for Sir Tom who celebrated his 80th birthday last year.
Stevie was seen singing Tom's hit It's Not Unusual before saying: "I had the pleasure of not just meeting that person who sang that song but meeting a new friend.
"And I know that that friendship will last for a lifetime.
"So many wonderful moments we've shared. I still remember when we did your show and I was telling you the words to Uptight, you were telling me the words to It's Not Unusual. I played drums and it was just a wonderful thing.
"I love you with my whole heart and I want you to promise me that you will do your best to give us another 80 years."
An emotional Tom commented to his fellow judges: "He's a wonderful person and it was a pleasure to sing with him.
"I hope I can sing with him again sometime."
Hosted as usual by Emma Willis, The Voice UK continues on Saturday nights on ITV.
You can watch The Voice UK 2021 online via the ITV Hub.
Acts who make it through the blind auditions will go on to take part in the battle rounds later in the series.