When it comes to rejigging a classic film like 'Ghostbusters', the casting is crucial.

For many people, that film was the essence of their childhood - so the fact that Paul Rudd has joined the fray for Jason Reitman's 'extension' of the original 1984 film has been met with much whooping and hollering.

Rudd broke the news on Twitter, posting a video of himself in front of the famous fire station from the original.

"You see, this is what happens, every day, people coming out to take pictures of this magnificent building, and really, can you blame them?’ he said in the clip. "It’s such an epic film. I love it, I’m a fan. When I heard that Jason Reitman was going to be doing a new version in the fall, my agent called up and said, “Hey, Jason, we hear there’s a part of a young – semi-young – strapping man that needs to be cast, who you gonna call?”

"When I heard they were going call me… well, as you can imagine, I nearly slimed myself. I can’t wait to join the cast this fall for Ghostbusters. In fact, I'm sliming myself right now."

Reitman, whose father Ivan directed and starred in the original, told Variety: "I've been wanting to work with Paul Rudd since my short film opened for 'Wet Hot American Summer' at Sundance. Thrilled he'll be joining this new chapter in the original 'Ghostbusters' universe."

https://www.youtube.com/watch?v=38lxJSevihw

Rudd will play a teacher in the film, which is set for a summer 2020 release and has no official title as yet. He'll join Carrie Coon and Finn Wolfhard ('Stranger Things') in the cast. Original stars Bill Murray, Sigourney Weaver and Dan Ackroyd are believed to have roles in the film, too.

The news of Rudd's casting has gone down pretty well with fans...