Film: Director Feelgood

"I CAN'T remember the joke exactly, but I remember the punchline had to do with two scoops of ice cream," says Tom Shadyac. The director of Ace Ventura: Pet Detective, The Nutty Professor and Liar, Liar is thinking back to 1982, when he sold his first wisecrack to Bob Hope.

At 23 years old, Shadyac was the youngest hack in Hope's script-writing sweatshop. "Even when I was on vacation," says Shadyac ), "he would call me up and say something like: `I got to speak at a dinner for these football players, got any football jokes?' It was like being a doctor, you had to be on call 24 hours a day."

Then one day, after two and a half years, the phone stopped ringing. "I had to call another writer to find out what happened," remembers Shadyac. "Bob had heard I was doing my own stand-up and that was that. In a way it was a back-handed compliment. It was Bob saying: `I don't want you to be great for you, I just want you to be great for me.'"

Seventeen years later, Shadyac's still spookily young-looking, with an elfin face and flowing black locks. Meanwhile, he has also launched the film career of Oscar-contender Jim Carrey and relaunched the career of Eddie Murphy. His latest movie, the Robin Williams vehicle Patch Adams, was phenomenally successful in the States. Even if you're no fan of Williams's honey-baked ham, you have to admire the efficiency with which Shadyac tugs the audience's heartstrings.

But I'm intrigued. Shadyac saw through the bonhomie of Bob Hope. What about Hollywood's latest crop of funny guys? Shadyac looks uncomfortable. When he received the script for Ace Ventura, Shadyac rewrote it, arranged a meeting with the studio, then pitched them the "radical idea" of casting Jim Carrey.

"Jim says he'd been offered Ace Ventura before and kept turning it down," says Shadyac. "That is not my recollection. A couple of directors wouldn't even see him. Jim was a TV star."

But he's unwilling to say much more. Jim Carrey is "a sweet guy", Eddie Murphy is "sweet" and Robin Williams "is simply one of the most generous men I've ever met as a human being".

"Robin would have lunch almost every day with a kid from a charity. People don't know how good he is," Shadyac says.

But surely, there must be some million-dollar egos raging on set sometimes? "You're digging for dirt," Shadyac snaps. "I'm not going to criticise the media, because people like to hear the negative. I just think it's sad."

When I suggest that reporting an on-set stand-off is hardly incendiary, he becomes icy.

"Well, Robin is like his character, and that character gets angry sometimes because he's a human being. Does Robin walk on air? No. But if you're looking for when he screamed at me in his trailer one time - which I'm not even saying he did - I won't share that. It's a violation of our relationship. We have to protect the freedom to yell, because the creative process can be challenging."

Certainly, it must be challenging when "Robin and Eddie" won't rehearse or when Carrey spends five hours going over one line, but for Shadyac these foibles simply point to professionalism.

"It's no accident that people fall in love with these stars," he argues. "These guys are showing you some pretty likeable characters and that's just how they are."

Shadyac's description of his actors feels dishonest - not because of what he says, but of what he doesn't say. In the fearful, feelgood universe which Shadyac inhabits, there's no room for messiness or complexity. That equals negativity. No, stars are "exceptional creatures" and Shadyac will serve them sunny-side up, off screen and on. Wonder what Bob Hope thinks of that.

`Patch Adams' is out on 12 March