Gabrielle "Gabz" Gardiner, 14, could have shown up at Britain's Got Talent in a fancy dress and neatly styled hair. But that's not her style. Instead, the young girl wore a printed "onesie" matched to a NY cap, all set and ready to rap -- at the piano. The judges gave her style a thumbs-up, and her own composition sent her through to the BGT live shows. Simon Cowell was impressed with her song, and the audience couldn't get it off their mind.

Gardiner told the BGT panel she has only been playing the piano for two years. You would think she has got to have some massive confidence. Taking 2 years of piano practice in a reality-based TV competition is an act of mad courage. But then there's more. The young girl later told the judges she was going to perform her own song.

"Do you think you can win?" Amanda Holden asked Gardiner. "Uhm, I hope so." The seemingly shy girl responds reluctantly. "Why?" Simon Cowell asked. "Uhm, 'cause I want to," she giggled. The audience laughed. "Good answer," Simon said, smiling.

"Put your lighters in the sky, if you're sleeping 'lone tonight, 'cause you've lost the one," says the lyrics of "The One" by Gabz Gardiner. She told the BGT judges the song is about "losing the love of your life." Such a tragedy hasn't happened to her, she said, but the song was inspired by some movies she's seen.

"Put your lighters in the air, if you've ever been scared, 'cause you've lost the one," Gabz' song says. The words may be a bit off and clumsy in parts, but the melody Gardiner has created proved to be a sensation in the making. Everyone has caught the tune of "The One" even before Gabz finished her song. The fact that she rapped while at the piano doing her own song was very charming, too.

"If you can write a song like that at 14 years old, who knows what you can do. We'd be crazy to let you go," said David Walliams.

Cowell pointed out Gardiner is "not the best piano player in the world," but noted her song could make it big if properly produced. "I think we're looking at a future pop star," he said.

Gardiner joined 23 others, including young comedian Jack Caroll for the Britain's Got Talent live shows.

VIDEO: Gabrielle Gabz Gardiner, 14, Raps Own Catchy Song 'The One' at the Piano

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