In Saturdays episode, we met 42-year-old singer Lifford Shillingford from South London.
He revealed he had previously enjoyed brief success in the early 00s, appearing on the Artful Dodger's hit Please Don't Turn Me On.
Lifford sang ‘A Change Is Gonna Come’ by Sam Cooke and his performance saw Alesha Dixon hitting the golden buzzer.
But his past connection with Alesha resulted in some viewers branding it 'unfair'.
Standing before the judges, Lifford and Alesha immediately recognised one another from her Mis-Teeq days.
"I know him," Alesha remarked. "Good to see you!"
Lifford revealed: "We were on the circuit together, they [Mis-Teeq] were headlining, I think they liked them a little bit more!"
Now Alesha has responded to the criticism, insisting that the pair aren't close friends.
"He’s not a friend, that sounds cold, but I don’t have his phone number. I haven’t seen him in years," she told the Daily Mirror newspaper. "When I say I know him, I know his music.
"I remember him from back in the day, there were shows that Mis-teeq were doing that he was too. There was just a mutual respect and understanding between us.'
On the show, Alesha explained her decision to hit the golden buzzer: "It felt right. I feel like it takes courage and bravery when you've been in the industry and it knocks you down and you came back.
"For you to be on that stage just singing raw, heart and soul, you deserve this moment."
With Alesha's golden buzzer, Lifford goes straight through to the live semi-finals later in the year.
At the end of the series, just one act will walk away with £250,000 and a spot on the Royal Variety Performance.
Britain’s Got Talent continues Saturday nights on ITV.