"It's almost like your brain tells you to do something which you shouldn't be doing but you just go along with it. The next thing is, you've actually fallen asleep.
"I always said I wanted to find a cat that could play the guitar," he added. "I think we've done pretty well finding a dog that can hypnotise people! I just want to own the dog.
"I could literally rule the world with this dog because all it does is stare at you and you do whatever it wants."
Fellow judge David Walliams said: "Simon being hypnotised by a dog was quite peculiar because he was very keen to get on stage to be hypnotised by this dog. We didn't quite believe he had been hypnotised, but on reflection I think he was.
The spectators one by one fell to the floor after being put into a trance. Photo / Youtube / CCTV
"I think it was the woman hypnotising him and the dog was just there. It was a little bit disturbing. I was hoping that he might go under forever and stay in this hypnotised state, but he did come out of it."