See more from Britain's Got Talent at http://itv.com/talent
She's cute as a button, but don't get on the wrong side of this fearsome nine-year-old from County Armagh!
Jesse melts the Judges' hearts when she first appears on stage, but they're not expecting what happens next...
Could Simon have met his match?
SUBSCRIBE: http://bit.ly/BGTsub
Facebook: / bgt
Twitter: / bgt