Shansel said before her performance: "People don’t expect the music I sing to come out of me, it comes like quite a shock to me. My mum says I sound like a 30 year old."
And sure enough, the teenager left the panel gobsmacked when they turned around at the end of her performance of Nessun Dorma, with the stereotypical tanned Essex girl far from the mature performer they were probably expecting.
The likes of Jessie J and Sir Tom are left even more shocked after Shansel revealed that she hasn't even had any vocal training.
She laughed: “I was taking the mickey out of Katherine Jenkins on the TV and discovered I could do it quite well.”
Showing it wasn't always all about The Voice, Jessie J confessed: “I didn’t turn around because I thought you’d be a lot older, but I don’t think this will be the last we'll hear of you."
Will.i.am meanwhile was clearly annoyed at himself.
"I’m kicking myself in the butt right now because something told me to turn around because there’s the opportunity to reinvent radio," he told the youngster.
He added: “Then when you told me you were 17... It’s my fault, I missed an opportunity. I mean that."
Unfortunately there are no second chances on The Voice, for the artists or the coaches...