The tragic backstory of The Voice's Sarah Stone, whose mother vanished 17 years ago.

When Sarah Stone was just six years old, her mother dropped her off at school, just like any normal day.

It was the last time she ever saw her.

Sharing her story on last night’s episode of The Voice Australia, Sarah, now 22, revealed she is the daughter of Linda Anne Grimstone.

Linda, 42, was last seen on September 4, 2000, after dropping her two children - Sarah, and her older brother Alex, at Croydon Hills Primary School in Melbourne's north-east.

Her car was found the next morning in bushland around 270km north east of Melbourne. She remains number five on Australia's missing persons list.

"Mum just completely disappeared off the face of the earth," Sarah said on last night's show.

"Still to this day, no one really knows what happened with my mum. It's just something that we've had to deal with day to day."

"Dad's not ready to stop looking for her. Mum was his absolute soul mate. He adored her to the point where he still talks about her every day. Every single day," she said.

Now, 17 years later, Sarah is pursuing her dream of a music career, catching the attention of all four judges on the show.

She chose to join Boy George's team, who told her it was "impossible not to turn as her voice was so beautiful".

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