Fans of the show rushed to pay their respects in the comments, offering condolences to his family.
The singer appeared on the 2020 series of the talent show, and was known for famously blowing Simon Cowell away in his first audition.
Dave Betton, 82, was joined on stage alongside his son, Dean, and received a standing ovation for their rendition of Frank Sinatra’s ‘That’s Life.’
Amanda Holden claimed the father-son duo has ‘smashed’ their audition, while head judge Cowell said: “There are certain days I think what I need is a mug of hot chocolate – and you were a mug of hot chocolate!
“You made me feel good, I needed that.”
The two made it to the latter stages of the competition, after being kept in by a public vote.
Announcing the sad news, his son Dean wrote: “It is with a heavy heart and great sadness that I have to let you all know that the legend that is Dave Betton sadly passed away after a very brief illness, surrounded by his loved ones.
“Myself, my brother Darren, our wives, his grandsons and granddaughters, great grandsons and great granddaughters, extended family and all his friends will miss him dearly and he will leave us with a huge void to fill.”
He added: “Rest easy Pops and I hope Mum is giving you a big telling off for joining her far too soon. Love you always. From me and your loving Family.”
Prior to the death of his wife, Dave was a well-known club singer, before doing a tour in Australia and South Africa.
Following her death, his son became a musician, and made a career for himself as a Robbie Williams tribute act.
His funeral will be held on October 27, after suffering from sepsis.
Symptoms of the life-threatening illness include a fever, uncontrolled shivering, confusion, passing little urine, and a blotchy rash.