Sarah, a school girl and singer, originally closed this series' first round of try outs for the new series.
Currently living with her mum and dad Alex in Milton Keynes, Sarah belted out “And I Am Telling You” for the judges from the musical Dreamgirls.
After singing, Sarah had all four judges and the entire live audience up on their feet - before Simon Cowell hit the golden buzzer.
He said: "I've heard this song a lot and it started off really well and then it's like you became possessed halfway through.
"It was quite incredible and for someone of your age to stand on that stage with all the nerves and pressure to absolutely nail the song but you made it your song."
Simon's golden buzzer sent Sarah through to the live semi-finals this week where she wowed once again.
The teenager belted out Prince's Purple Rain to get a full standing ovation from the judges.
The panel had nothing but praise for Sarah but they won't be in charge of her fate tonight.
This year there is NO judges' vote in the BGT semi-final results.
Instead, the two acts with the highest votes from the public alone will go straight through to the final.
However the ten finalists chosen by the public will be joined by a wildcard picked by the judges who will then go head to head in the grand finale.
The Britain's Got Talent 2017 final is on this SATURDAY night, June 3.