Who, as the tagline for one of the most popular movies ever made asks, you gonna call? Not Ernie Hudson, it turns out. At least not first.

He's giving a talk at the London MCM Expo, where he's come to promote the new Ghostbusters game. But by his own admission, Hudson was not top choice for the job. "In the scheme of people who they go to, I'm like, the last guy," he tells the audience. "They assume I need the money. Which is true."

In fact, as Hudson explains later, he's done rather well out of Ghostbusters. Winston Zeddemore didn't get nearly as much screen time as the other three leads, but 24 years on the actor who played him is still recognised the world over. He's still getting paid to promote Ghostbusters products and he's still making money at sci-fi conventions.

He's arguably the star attraction at this one. Sure, Edward James Olmos is signing autographs over there in the corner. But Hudson was famous long before Olmos started shouting made-up swearwords at pretty robots, and besides, he's charging GBP 20 a time.

In typical circumstances Hudson would be doing the same. "Usually I do these conventions, and I sit at a table and I sell autographs to you guys for 15 pounds or something. Which is really kind of cheesy," he says. "But I'm down here for the guys who made the Ghostbusters game, so I'm here to sign for free. You can come by without worrying I'm going to take your money. If you want to take photos, feel free. Come by and say hello."

He's just as friendly when we sit down for our interview, full of smiles and promising to answer all my questions even if he's heard them a hundred times before. He doesn't pretend to be a huge gamer. "But my sons, they're really into games," Hudson says. "So when they asked me to do the voiceover for the game, one of my boys came with me. He played it and he really liked it a lot. He was very impressed with it."

Certainly more impressed than he was with the Commodore 64 Ghostbusters game. "My kids really hated that. They thought it sucked. When it's your movie and your kids are saying, 'Dad, this game really sucks,' it's kind of... Hmm. So hopefully this game will be better than the first game. Hopefully they'll like it, and you guys will like it."
'Ghostbusters' Ernie Hudson'

Go on Ernie! Stick it to the man! Or rather ghost.

It's not that Hudson's never played videogames, he explains. "Years ago, I bought my son Tetris. He said, 'Wow, this is cool, Dad, but are you sure you don't want to play? Here, this is how you do it...' So I start playing Tetris. I have to be at work at six o'clock the next morning. Then it's 4.30am and I've been up all night, playing Tetris."

It is a tragic and all-too familiar story; Hudson soon found himself in the grip of an addiction that would go on to almost consume him. "For 15 years, I was hooked on Tetris. I played it every single day," he confesses. "I can still hear that stupid song in my head. I thought, if that one game did that to me... I just don't have time for that. So I'm not a gamer. But the kids, they spend more time than I'd like to see them spend playing games."