The eccentric former MONTY PYTHON star felt sure he had landed the dream job when he was invited to fly to Los Angeles and meet Potter creator Jk Rowling and producers - but they handed the film to American Chris Columbus instead.
Gilliam recalls, "I was the perfect guy to do Harry Potter. I was reading the script as I was flying to Los Angeles for the meeting and I thought, 'Oh, she's (Rowling) seen TIME BANDITS, she's seen Monty Python - you know you're going to get the job.'
"The terrible thing about it was during the course of the meeting, I started getting enthusiastic; I was even getting myself excited.
"I remember leaving the meeting, getting in my car, and driving for about two hours along Mulholland Drive just so angry I'd allowed myself to get excited about it."
As a result of his disappointment, Gilliam admits he was far from impressed with the first two Potter movies.
He rants, "Chris Columbus' versions are terrible. Just dull. Pedestrian."