The Black Eyed Peas star was stunned when he heard Liz Oki sing George Michael's A Different Corner and told her how she reminded him of his aunt Stephanie who died recently.
A visibly stunned Will told her: "Um, I had my back turned, when you sung the words 'I'm so scared' and I thought of my Auntie Stephanie and she passed away on Easter and um, my grandma passed away on Thanksgiving and I told myself that my aunt passed away to be with my grandma, but I know she was afraid, you know?
"My aunt used to sing for the whole family and we used to hold hands and pray for our family dinners and when I turn around you look... I mean you have the same skin complexion and I thank you for singing today."
Fellow coaches Sir Tom Jones, Kylie Minogue and Ricky Wilson all wiped away tears as Will.i.am spoke to Liz, who explained she was still getting over the loss of her adopted mother only two weeks before her audition.
She told them: "I grew up in two children's homes, in a babies home in Woking until I was five, and then a children's home in Harrogate, Yorkshire until I was 15.
"The lady I called mum, was the one constant in my life right from when I was a child and has probably known me longer than anyone else I know. She passed two weeks ago."