David Walliams told the youngster to improve his singing voice three years ago when the city lad was aged just 12.
But the comedian was made to eat his words last night as Kyle's flawless rendition of the emotional track Hallelujah wowed the judges.
Walliams then became the first judge to press the golden buzzer, which automatically sent Kyle straight through to the semi-finals.
After the 15-year-old had finished the song, Walliams said: “I thought it was really good. Well done Kyle.
"It was a really, really moving performance and I’m really glad that you came back and proved me wrong."
Simon Cowell added: “You gave every single ounce you could possibly give to that performance. This just shows you that when somebody grinds you down and says you are not good enough, you come back, and you look them in the eye, and you go 'I am good enough'."
Fellow judge Alesha Dixon described his story as being like a “fairytale.”
After the triumphant audition, Kyle told how his dream was made possible after his family paid for his tuition.
He said: “Back then I thought I was really good, the best thing since sliced bread.
“But David kind of put me in my place. I was absolutely gutted but he was spot-on what he said. I haven’t looked back since then to be honest.
“So I sat down and thought about it, and the day after I went to my mum and dad and I went: ‘I need singing lessons.’
“My nanan and grandad have paid for them every day since three years ago. It’s £15 every 30 minutes, and once a week, so it’s a lot of money.
“But they are thrilled for me now.
“They couldn’t be there as my grandad is in hospital with cancer, but he was waiting by the phone to hear, and he was so happy when I told him.
“I am going to dedicate my semi-final song to him, because he’ll be watching, and I 100 per cent want to try to win this for him.”
At the other end of the age spectrum, The Pensionaires' Malcolm, aged 75, and Henry, aged 84, from Doncaster, also earned glowing praise.
They got a yes vote from all the judges and Cowell joked: "I want to hear you sing Let's Get Ready To Rumble.
"You are the kind of act that you feel good after seeing."