Britain's Got Talent 2015: Simon Cowell cries after The Neales join Isaac Waddington in the final

Turns out the music mogul hasn't got a heart of stone after all

Family vocal group The Neales moved Simon Cowell to tears with their semi-final performance of 'Father and Son' to win the judges vote and go through to the final (Syco/Thames/Corbis)

He's known for his harsh judging and impossibly high standards but last night's Britain's Got Talent semi-final saw Simon Cowell moved to tears.

Four-piece vocal group The Neales - made up of solicitor Laurie Neale and his three sons - sang Cat Stevens classic "Father and Son" against a backdrop of home videos to leave the music mogul feeling "quite emotional". Something to do with his own son Eric perhaps?

"God what's happened to me?" he said after their performance with David Walliams chiming in that he too had almost welled up at their "sort of cheesy but heartwarming" effort.

"People are going to connect with you because the most important thing in the world is family," Alesha Dixon added, with Amanda Holden left "completely choked up".

"I mean, to make Simon cry..." she said. "He cried! His mascara's running!"

Isaac Waddington won the public vote in the last semi-final to go straight through to the final after Alesha praised the 15-year-old singer-songwriter's "hypnotic" voice and Simon described his performance as "fantastic".

It was then between The Neales and fun dance troupe Boyband, chosen as hosts Ant and Dec's Golden Buzzer act earlier in the series.

Simon chose to save Boyband despite his strong response to The Neales, but the other three judges opted for the family group meaning they will join Waddington for Sunday night's nail-biting climax.

Magician Jamie Raven, dog act Jules and Matisse and Welsh choir Cor Glanaethwy are among the acts competing for a £250,000 cash prize and the opportunity to join the Royal Variety Performance.