Just Us, a team of five female teenagers from the Wirral, appeared before the judges in the ITV show's latest episode.
It was a particularly poignant moment for leader Julia, who suffers from scoliosis.
"It's a curvature of the spine. My one's quite rare," she explained. "It's more common to have an accident and get it, but I was born with it.
"I have to have surgery soon, and after surgery I won't be able to dance. This is like, my last chance, because I've always wanted to do it."
A stunned Simon Cowell praised her, saying: "You've got an amazing attitude, you really have."
The group then performed their moving routine, aptly set to Rachel Platten hit 'Fight Song'.
It was met with a standing ovation from the audience and the panel.
"That was an absolutely stunning performance," David Walliams said. "We were all hoping and praying it would be fantastic, and it far exceeded our expectations."
Amanda Holden added: "Your friendship and strength together is just fantastic, it's lovely to watch."
But the display particularly struck a nerve with Strictly Come Dancing winner Alesha Dixon.
Struggling to hold back tears, she said: "I have so much admiration for you girls right now, I can't tell you.
"When you're passionate about something… I could not imagine not being able to ever do that again. I really couldn't. That's why we all love for the things that we love to do.
"It really touched me, so much so that I'm gonna do this."
Alesha then hit the Golden Buzzer, guaranteeing Just Us a place in the live shows.
She joined them on stage for a group hug, with Julia telling her: "You've made my dreams come true."
Just Us join Sarah Ikumu in the Golden Buzzer line-up, with David, Amanda and hosts Ant and Dec yet to reveal their picks.
The judges have been full of praise for Alesha's choice, with Amanda recently commenting the dancers "could win the whole show".