'TBBT, 'Young Sheldon' stars reflects on working with Bob Newhart

The Big Bang Theory and Young Sheldon stars are mourning the death of legendary actor Bob Newhart after his death at 94.

The iconic comedian and actor, who died on Thursday, July 18 following a series of short illnesses, performed final acting scenes as Professor Proton on The Big Bang Theory and its prequel on nine episodes between 2013 and 2020.

Following to Newhart’s publicist confirming his death, co-stars from both critically acclaimed shows paid tribute to the deceased star.

In a statement to People, The Big Bang Theory actress Mayim Bialik shared how Newhart made an impact on her acting career.

"As a child, the Bob Newhart Show provided countless hours of enjoyment for me – it constituted some of my earliest training in the art of sitcom," she told the outlet, adding that working with him was a dream come true moment for her.

"He was effortlessly professional, poised, hilarious and incredibly approachable," she concluded, "How he will be missed!"

In addition, Young Sheldon star Iain Armitage took to his Instagram Stories to mourn the death of the "inspiring" actor.

"Thanks for being such an inspiring Professor Proton and such an incredible human being," he wrote in a slide, over a photo of Newhart as Professor Proton.

"Thinking of you and all who loved you today," he added in the slide with a row of broken heart emojis.

Other The Big Bang Theory co-stars who remembered Newhart includes, Kaley Cuoco, Kunal Nayyar, Bill Prady and more.