Ghostbusters' Ernie Hudson

"Danny [Akroyd] and Harold [Ramis] wrote an earlier script. They were trying to create a way where we could turn the franchise over to some younger guys, but they just couldn't get Bill to sign off on it," Hudson says.

"I know they've been wanting to make it happen, they've been trying. But I'm told Bill Murray has been the hold-out. I'm not quite sure why they have to have his approval. Something is going on there. But I know it wasn't from a lack of interest from the studio, or from a lack of interest from Harold and Danny."

So would Hudson sign up to appear in a new Ghostbusters sequel? "Me? Hah! Please," he jokes. "As long as they pay me well. My oldest son would tell me not to say that. But the truth of the matter is, I can be bought off." And then he adds, brilliantly, "For the right amount of money, I'll believe anything you say."

The rest of the interview passes in a bit of a blur, as I have fallen completely in love with Ernie Hudson. He may be the fourth person they call, but with his big smiles and funny jokes and charm and honesty, he could sell me anything. I am transfixed as he tells a story about a party at Ray Parker Jr.'s place ("His house is twice the size of mine. That song really paid well"). I am strangely fascinated to learn he missed breakfast with Edward James Olmos earlier. I could sit here all day.

But I can't, it turns out; the PR man is signalling I have one question left. Except I don't have any questions left, just a notepad full of scrawls about downloadable content and why movie tie-ins are rubbish and none of it seems relevant. So I scratch around in the depths of my brain, and somehow manage to come up with the worst interview question ever: "What's the best thing about being a Ghostbuster?"

"Hmm," says Hudson, while I attempt to pull my own head between my shoulderblades in shame. "I don't know if this is about being a Ghostbuster or an actor or whatever, but...

"Sometimes when I'm walking down the street, anywhere in the world, I see somebody on the other side of the street, and you can just tell his life sucks by the way he's walking. There's a cloud over his head. You see people who are homeless, who are having a hard time.

"They look up and see me, and they recognise me. And they go, 'Oh, sh**! Oh man! Oh wow!", and the cloud kind of disappears. They say, 'Wow, man, we're really happy to meet you.' Then they say - I get this all the time now - 'You're my mother's favourite actor. Can you sign this?'

"After that little exchange they walk away, but it's a different walk. That doesn't cost any money. And I think it's pretty cool."

Few people could tell a story about making homeless people happy without sounding arrogant, but Ernie Hudson can. Partly because he tells it with humour, and partly because you can tell meeting him makes people happy. I go to shake his hand and he gives me a bearhug instead, and I walk away thinking, 'I just hugged a Ghostbuster.' And it is a different walk.