'Bombshell' star John Lithgow jokes about why he's cast as 'old, fat, bald guys'

John Lithgow can now add Roger Ailes to his storied career resume.

In his new film "Bombshell," Lithgow underwent a complete transformation to portray the former chairman and CEO of Fox News.

The award-winning actor told "Good Morning America" that he's realized "people want me to play old, fat, bald guys" after being cast as Ailes and Winston Churchill.

"They spent just as much time every morning with Charlize Theron and Nicole Kidman, I mean look at those amazing transformations," he said of the film's makeup crew. "In my case, he added about 300 pounds in my face alone."

Bringing this story to the silver screen alongside a powerhouse cast of leading ladies was "phenomenal," Lithgow said.

"It was wonderful, I mean it was like the best repertory company you could put into a movie," he explained, hailing the whole ensemble, which also includes Margot Robbie, Kate McKinnon, Connie Britton, Allison Janney and more.

"Charlize incidentally was our producer. The movie never would have happened without her," Lithgow said.

When he first saw himself as the disgraced network executive, "it was pretty startling it takes you a while to get used to yourself," Lithgow said.

"It so completely changes your sense of yourself, which is a wonderful big step forward when you're playing a role," he added. "It's extreme."

Plus, it was quite a drastic difference from the preparation it took to get into his Emmy Award-winning role on "The Crown."

"I didn't use much makeup oddly enough playing Winston Churchill. Turns out I look a lot more like Winston Churchill than I realized," he said with a laugh.

Of all the characters Lithgow has played, he said "the whole experience of 'The Crown' was completely wonderful playing Winston Churchill."

"I certainly didn't think of myself as either of these men," he said of his latest two roles as Ailes and Churchiill.

"When I was offered both these roles I thought people were crazy, but I wasn't about to say no," he said. "Incredible characters, one known as one of the great men -- and the other one of the most disgraced men."

Lithgow also spoke fondly of a character that he said added years to his life.

"And '3rd Rock from the Sun' -- I mean that was six years of nonstop laughter," he said of the comedy sitcom about an alien family disguised as humans. "It was just so much fun -- I mean I think it prolonged my life six years."

"Bombshell" is now in theaters nationwide.