The 'Price Tag' hitmaker - who won the Critics' Choice gong at last month's awards - admitted she has doubted her abilities as a singer in the past, but the accolade has made her believe in herself.
Showing her personalised BRIT Award on UK TV show 'Daybreak', she said: "Imagine if they had spelled my name wrong? Good toilet roll holder there, thanks!
"You always have to have self-belief because if you don't believe in yourself then no one else will believe in you. I think I doubted sometimes my situation and sometimes the people around me, but I always have so much passion and love for what I do."
Despite being one of the hottest emerging stars in the UK, the 22 year old explained she hasn't always been praised for her talents, and was even banned from the school choir as a child for being "too loud".
Jessie - real name Jessica Cornish - added: "I wasn't allowed in the school choir. So if you're watching music teacher, I'm not going to name and shame you. But yes, at 11 years old, can you imagine?
"They basically just said that other parents could complain. So I didn't do music at school, I wasn't in the choir, I didn't do the plays, I kind of just kept myself to myself."
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