Cast members from Big Bang Theory and Young Sheldon pay a heartfelt tribute to the legendary Bob Newhart

“When I got to work with alongside him on TBBT, it was absolutely a dream come true,” Mayim Bialik tells PEOPLE about Newhart, who she characterized as “poised, hilarious, and incredibly approachable.”

Jerry Digney, the comic’s publicist, confirmed to PEOPLE that the iconic comedian died on Thursday, July 18, at his home in Los Angeles, Calif., after a series of brief illnesses. He was 94.

His final acting role was as Professor Proton (actual name Arthur Jeffries) on The Big Bang Theory and its prequel offshoot, Young Sheldon, in nine episodes broadcast between 2013 and 2020.

Arthur, as Professor Proton, presented an instructive children’s science show that Sheldon (Jim Parsons) and Leonard (Johnny Galecki) grew up watching. Arthur was also Sheldon’s boyhood hero, and the two first met in a season 6 episode of the show when he and Leonard hired him for what he assumed would be a children’s party. Instead, the older boys simply wanted to spend time with Arthur because he inspired them to become scientists.

He appears in six episodes of the comedy before making guest appearances on the spinoff.

After Newhart died on Thursday, cast members from both programs paid homage to him.

In an exclusive message to PEOPLE, Mayim Bialik of The Big Bang Theory discussed Newhart’s influence on her life.

“As a youngster, the Bob Newhart Show gave me numerous hours of entertainment and also served as part of my early training in the art of comedy. ” Working with him on TBBT was a dream come true,” she remarked. “He was effortlessly professional, poised, humorous, and very engaging. Working with Bob meant being with a real comic legend, the likes of whom we just don’t see anymore. He will be greatly missed!”

“Bob’s Professor Proton inspired Sheldon, and I was inspired by his acting career. “He was loved and will be missed,” Armitage said.

On Thursday, the 16-year-old paid tribute to Newhart via Instagram Stories. “Thanks for being such an inspiring Professor Proton and such an incredible human being,” he wrote on a slide that featured a shot of Newhart as Professor Proton. “I’m thinking of you and all those who loved you today.”

He included a succession of broken heart emoticons in the presentation.

Kaley Cuoco, who played Johnny Galecki’s love interest Penny on The Big Bang Theory, paid tribute to Newhart on Instagram.

“Experiencing Bob Newhart, the genius, fulfilled a lifelong dream. He embodied class, kindness, generosity, and humor,” she remarked, accompanied by a photo of herself and the Elf actor from a series scene. “Each take, every time. “Icon forever.”

Kunal Nayyar, who portrayed astrophysicist Rajesh “Raj” Ramayan Koothrappal on TBBT, captioned a shot on his Instagram Stories on Thursday, “Professor Proton.” Our lovely Bob Newhart. RIP. “I’ll miss you forever.”

Bill Prady, the co-creator of The Big Bang Theory, also paid respect to the late comic on X (previously Twitter).

In a post featuring a photo of himself and the Legally Blonde 2: Red White & Blonde star smiling together, he said, “Hard to explain how important Bob Newhart was to every comedian and comedy writer who came after him.” “Working with him ever so briefly was one of the greatest joys and honors of my life.”

Aside from The Big Bang Theory and Young Sheldon, Newhart had a lengthy history of television and cinema roles.

With almost six decades in show business, the renowned performer was best known for appearing in the CBS shows The Bob Newhart Show (1972–1978) and Newhart (1982–1990).

His stand-up comedy, deadpan humor, and roles in Legally Blonde 2, Elf, ER, and the TNT film The Librarian: The Curse of the Judas Chalice also earned him recognition.

Sons Robert and Timothy, daughters Jennifer and Courtney, and ten grandchildren survive Newhart. His wife, Ginnie, whom he married in 1963, died in April 2023.