According to Digital Spy, the former Spice Girls star was serving her first day as a guest judge on the talent show yesterday, when she 'insulted' an 81-year-old widower from Birmingham called Lou.
She said of his performance: "I wanted to fall asleep."
This reportedly drew boos of disapproval from the crowd.
The audition also saw judge Louis Walsh taking the mickey out of Gary Barlow by calling him "Sir Gary" in front of the audience, a reference to his work organising the Queen's Diamond Jubilee concert - which it is speculated could earn him a knighthood.
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