NEW YORK--Last year at this time, Robin Williams was conducting seances with 1950s screen star Fred MacMurray.
Williams had been approached by Disney to do a modern version of MacMurray's 1961 classic Disney comedy The Absent Minded Professor.
Professor was the biggest box-office hit of 1961, and John (Home Alone) Hughes had developed a new version called Flubber with Williams in mind.
"Fred definitely informed me from the grave, but it was my sons Zachary and Cody who made the actual decisions for me," explains Williams.
"We watched the video together and they loved it. They told me I had to do the film."
Zach, 14, and Cody, 6, were also responsible for the wild basketball sequence in Flubber.
"There was a very funny basketball sequence in the original, but John Hughes and the studio figured there had been too many wacky basketball movies recently, so they cut it out," says Williams.
"I told them it had to go back in because Cody in particular laughed uncontrollably during the scene in Professor."
It didn't surprise director Les Mayfield that he was suddenly prepping a basketball sequence that has Williams and five pint-sized players flying, flipping and rolling through the air.
"Robin is a very powerful man. He can do and get most anything he wants. People in Hollywood listen to him because he's usually dead on when it comes to knowing what his audiences want from him."
One of the main reasons Disney wanted Williams in Flubber was that he is such an incredible mime artist. The creature in Flubber is entirely computer-generated.
"Not one speck of green goo ever appeared on set," said Mayfield.
"That meant Robin had to mime talking to, holding, chasing and catching the flubber. We'd tell Robin what we intended to do in the computers, and he ran with it."
Sometimes Williams would run further than the special-effects wizards.
"Just as he did with the genie in Aladdin, Robin would improvise and it would be so funny we just couldn't cut it out.
"We'd have to go back into the labs and extend whole scenes."
Marcia Gay Harden, who plays Williams' love interest, says: "Robin is as unpredictable as the flubber. You never know what Robin's going to do when the cameras start rolling.
"Laughter follows Robin wherever he goes. You always know where he is on the set. If there's gales of laughter at the catering table, you know he's there.
"If laughter erupts in a washroom, you don't have to ask why."
Williams insists that for once he's playing the straight man in a film.
"The flubber is the one who gets the laughs. I just set him up. Not even I can upstage a green glob that does a mambo."
In Flubber, Williams shares top billing with another scene-stealer. She is a flying saucer computer named WEEBO who has a crush on her creator.
Her voice is supplied by Jodi Benson, the voice of Ariel in The Little Mermaid.
Whenever WEEBO speaks, she pops her lid and shows a corresponding movie clip on a video screen.
In the original film, the professor's best friend was a dog, but Williams says WEEBO is a great addition--especially for girls.
"My daughter Zelda went around the house talking like WEEBO."
The little computer was operated by technicians. All her wires were erased in the labs at the same time the flubber effects were being added.
Though Williams tries to down play his contributions to the flubber, Mayfield explains that "from the beginning we wanted the flubber to be an extension of Robin.
"That's why we have Robin add a strand of his hair to the experiment. The flubber has his DNA so it is really Robin's alter ego.
"Whenever we were stumped with how to portray the flubber in a sequence, we asked ourselves how Robin would have behaved as an adolescent."
This was particularly true when Mayfield and the special-effects crew were creating the mambo sequence.
"The flubber had to dance, so we taped Robin dancing to the mambo and then gave the flubber his moves."
Flubber opens Wednesday.