Co-star Harold Ramis has confirmed the funnyman will be reprising his role as Dr. Peter Venkman in the follow-up to 1989's Ghostbusters Ii.
The news comes after Murray stunned reporters on the red carpet at the recent Hyde Park on Hudson premiere by revealing he was considering returning to the franchise.
Before that, fans and castmate Dan Aykroyd, who has been championing the third film for years, had all but given up hope that Murray would return - this past summer (12), the Canadian actor, who played Dr. Raymond Stantz in the first two Ghostbusters films, told Metro magazine the project would be moving on without its star.
Aykroyd said, "He (Murray) won't be involved... It's sad but we're passing it on to a new generation. Ghostbusters 3 can be a successful movie without Bill. My preference would be to have him involved but at this point he doesn't seem to be coming and we have to move on. It's time to make the third one."
But it seems there has been a change of plan.
Ramis has received word that Murray was agreeing to the project.
He tells SuperOfficialNews.com, "It was kind of crazy. Just out of nowhere, I get a phone call from Bill at almost three in the morning... and he simply said, 'Yeah, Ok, I'm in!' That's Bill Murray for you. Surprising and straight to the point.
"Bill also said a major factor in his decision to do the movie had been all the support he received from fans."
And co-writer Paul Horner is thrilled about the news, adding, "Word through the grapevine was that Murray enjoyed reading our script that was passed along to him a few months ago. As for if he was going to be a part of it, well that was the million-dollar question. The writers, the cast, the fans... Everyone is truly excited for this to have finally all come together."
Ivan Reitman, who directed Ghostbusters 1 and 2, will return for the third film. Sigourney Weaver will also return as Dana Barrett, and reports suggest Rick Moranis will come out of retirement to reprise his role as Louis Tully. Ashton Kutcher, Seth Rogen and Vincent Kartheiser have been suggested as cast newcomers - and possibly the faces of the new Ghostbusters.
Shooting is scheduled to begin next year (13).