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In an interview with Esquire, the comedy veteran has said that he and director Ivan Reitman are 'closer than we ever have been' to getting the movie rolling.
But he also confirmed that Bill Murray won't be joining them, though the door will always remain open should he change his mind.
"At this point, I think we're closer than we ever have been."
It seems also that the production can move ahead without Murray's consent.
"I'm not sure Billy [has to sign on] anymore, since he abrogated his rights by sort of saying, two years ago, 'I don't want to be involved'," he said. "The picture company I think had some clause in there that if he actually passed on the third of fourth offer, he no longer has a view of the franchise.
"We have to move on, but we'll always leave a hole for him. He's always there. He can always come back at any time and be rebuilt into it, as far as I'm concerned. That's up to his lawyer and the picture company to work out, but creatively, he will always be a part of it."
But Aykroyd added that if it does not eventually come to fruition, he won't be too broken up about it.
"If it does not happen, the life of Dan Aykroyd and his family and friends will be quite full without Ghostbusters 3," he added.
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Ben Arnold writes for Yahoo! Movies UK&IE