Ivan Reitman, the influential director and producer of wildly popular comedies "Ghostbusters," "National Lampoon's Animal House" and "Twins," has died aged 75.

On Monday Reitman's son Jason -- himself a director of films such as "Juno" and "Ghostbusters: Afterlife" -- tweeted: "I've lost my hero."

Arnold Schwarzenegger, who moved from violent action films into comedies "Twins," "Kindergarten Cop" and "Junior" thanks to Reitman, led the praise from across Hollywood for a "legend" and "comedy royalty."

"I'll always be grateful that he took a chance on this Austrian action-hero in a comedy during a time when the studios just wanted me to focus on finding new ways to kill bad guys, blow things up, and show off some muscles," said Schwarzenegger.

"I can't believe I won't work with him again or hang out with him again or just schmooze about life again," added Schwarzenegger, who had been due to collaborate with Reitman in the sequel "Triplets."

Over his decades-long career Reitman produced and directed films that helped establish major comedic stars such as Bill Murray, who as well as starring in "Ghostbusters" also appeared in Reitman hits "Meatballs" and "Stripes."

Reitman produced the 1978 hit "National Lampoon's Animal House," which became one of the most beloved and chaotic depictions of the system of fraternities and sororities in US colleges.

But it was 1984's "Ghostbusters" -- one of the most popular comedies ever made -- that launched a Hollywood dynasty.

The story of four men dressed in a version of firefighting gear tackling marshmallow monsters and slimy green spirits in a bid to save New York from a supernatural takeover has spawned several sequels and reboots.

The outfits worn by its four stars remain one of the most popular and recognizable Halloween costumes to this day.

"I am deeply saddened by the loss of Ivan Reitman. Truly a great man and filmmaker who I had honor and privilege of knowing and working with," tweeted Ernie Hudson, who played Ghostbuster Winston Zeddemore in the original and its 1989 sequel, and had a cameo in the 2016 reboot.

Ivan Reitman, pictured here in 2021, has passed away aged 75
Ivan Reitman, pictured here in 2021, has passed away aged 75 GETTY IMAGES NORTH AMERICA via AFP / Theo Wargo

"I'm in absolute shock," tweeted Paul Feig, who directed the 2016 version with an all-female cast of Ghostbusters.

"I had the honor of working so closely with Ivan and it was always such a learning experience. He directed some of my favorite comedies of all time. All of us in comedy owe him so very much. Thank you for everything, Ivan. Truly."

Tom Rothman, CEO of Sony Pictures which owns "Ghostbusters" studio Columbia Pictures, praised "a great talent and even finer man."

"Tonight, the lady with the torch weeps, as do all of us at Columbia, and film lovers around the world," wrote Rothman in a statement on Twitter, referring to the historic Hollywood studio's logo.

Reitman was born in Komarno, in what is now Slovakia, on October 27, 1946.

His Jewish parents survived the Nazis but, four years after his birth, fled Czechoslovakia to escape communism.

They eventually made their home in Toronto.

He is survived by his son Jason, and daughters Catherine -- also an actor and producer -- and Caroline.

"He came from a family of survivors and turned his legacy into laughter," wrote Jason.

"Thank you for the kind messages. Enjoy his movies and remember his storytelling gifts. Nothing would make him happier."