Here is what Cranston told me when I interviewed him for The Hollywood Reporter:

“If you’re playing a character who is nonfictional, there is an added respon­sibility: Lyndon Johnson, say, or Dalton Trumbo.

There is a plethora of source material, and Trumbo’s two daughters, Nikola and Mitzi, are still alive, and even though they were children at the time, I would ask them a bunch of questions.

For instance, an earlier iteration had Trumbo tell his kids to hop in the car, and he takes them for ice cream. Nikola and Mitzi giggled — that was Cleo, their mom, especially during the blacklist years. Cleo clearly was the emotional foundation and kept the fires burning at home.

As much of a vulnerable, noble battle that Trumbo was embroiled in, there was also some selfishness. We had really honest exchanges about how irritable and angry and impatient he could be. It is important to know that the families of these blacklisted writers and directors paid a price and suffered as much as the men themselves.”