Who are Just Us?

The dance group is made up of best friends Alice (17), Poppy (14), Julia (15), Annie (17) and Rebecca (16). They met at their local dance school.

What do Just Us do?

The dance troupe formed as a group after dancing a LOT at Poppy's house, and realising they had potential as a five-piece. An excitable Julia exclaims: “I’ve watched BGT all my life and I’ve always dreamt of being on it. Sitting here is really amazing – I'm shaking!"

However, their performance is tinged with a lot of sadness after Julia reveals she suffers from scoliosis.

Alesha Dixon was moved to tears and hit her Golden Buzzer for the five girls, sending them straight through to the live semi-finals.

"I have so much admiration for you girls right now, I cant tell you," the judge said. "And just seeing how you all come together with this beautiful friendship that you’ve got, and when you’re passionate about something, I could not imagine not being able to do that again. I really couldn’t. And that’s why we all live for the things that we love to do, it really touched me."

Joining the girls on stage, Dixon added: "I know what it means to have something that means more than anything in the world."

What is scoliosis?

As Julia explains, it's a curvature of the spine and her condition is quite rare as she was born with it. She reveals that she has to have surgery soon, and after surgery she won't be able to dance. This is her last chance to perform. And perform they do, and knowing Julia's story only makes their amazing routine all the more devastating.

According to NHS Choices, scoliosis can affect people of any age, but most often starts in children aged 10-15. Symptoms include a curved spine, leaning to one side and uneven shoulders. Many people don't need treatment but a small number will need to have surgery on their spine.

If Just Us don't bring a tear to your eye, we don't know what will...

Britain's Got Talent airs on Saturday April 22 at 8pm on ITV.