Who you gonna call?

On Monday, Josh Gad brought the cast of the 1984 classic “Ghostbusters” back together for a new episode of his web series “Reunited Apart”.

The reunion featured appearances by Bill Murray, Dan Aykroyd, Sigourney Weaver, Ernie Hudson, Annie Pots, director Ivan Reitman and his son and “Ghostbusters: Afterlife” director Jason Reitman.

RELATED: Bill Murray Confirms He’ll Return As Peter Venkman In ‘Ghostbusters: Afterlife’: ‘The Script Is Good’

The cast reflected on memories from the set, the impact of the film over the years and more.

Murray wore a sailor’s cap in reference to the giant Stay Puft Marshmallow Man from the film.

The actor revealed that he agreed to star in the film after reading only 27 pages of Aykrod’s original draft.

“I thought, ‘This is the best thing I’ve seen,'” he said. “I called him back and said, ‘I’m in.'”

Aykrod also said that about 80 per cent of the film’s dialogue was improvised on-set.

Among the many other revelations shared during the reunion, one of the most notable was that Reitman originally approached John Candy to play the role of Louis Tully.

“He didn’t really get it,” Reitman recalled, “He kept wanting to play him with a German accent, with a couple of German Shepherd dogs. I said, ‘I think that would be confusing given the dogs that are already on the roof.'”

The role eventually went to Rick Moranis instead.

“Rick read it and called me immediately and said, ‘John just made a terrible mistake, I’m so happy,'” the director said

RELATED: Finn Wolfhard Talks Auditioning For ‘Ghostbusters: Afterlife’

Also during the reunion, actor and “Ghostbusters” fan Kumail Nanjiani appeared on the call to quiz the cast on some of their more memorable lines from the film.

Later, musician Ray Parker Jr. joined the video chat to talk about writing the iconic theme song for the film, revealing that he composed it at the last minute.

He then played the song, while the cast and crew sang along

Viewers are also encouraged to donate to EJI, “an organization committed to ending mass incarceration and excessive punishment in the U.S., to challenging racial and economic justice, to protecting the most basic human rights for the most vulnerable people in American society.”

Previous episodes of “Reunited Apart” have brought together the casts of “The Goonies”, “The Lord of the Rings” and more.