Indeed, as seen onscreen, Penn was decked out in a full prosthetic face along with a balding head.
Speaking about the transformation, Roberts revealed in an interview that Penn spent hours longer in hair and makeup than she ever did.
"When I got to work, he would already look like John Mitchell, and then I'd be gone before he was transformed back into Sean Penn," she told E!
Meanwhile, the show's creator Robbie Pickering added that when Penn was cast, he insisted that he wanted to look as authentic as possible.
Roberts has also said that she only agreed to play Martha if Penn could play her husband in the series.
"I just thought [it] would be intriguing to Sean, and lo and behold, it was," Roberts said, per USA Today.
"He's great at portraying anything, but the idea of seeing him really inhabit and have this complete and total internal and external transformation into John Mitchell, it's pretty astonishing. To be up close to that every day was remarkable."
Who was John Mitchell?
John Mitchell was the Attorney General of the United States under President Richard Nixon, remaining in office from 1969 until he resigned in 1972, at which point he went on to manage President Nixon's re-election campaign.
When the Watergate break-in occurred in June that year, John went so far as to hire a former FBI agent to stop Martha from finding out about it. As Gaslit reveals, Martha did find out, and she leaked information about it as one of the key whistle blowers from the scandal.
As rumours swirled, John testified before the Senate Watergate Committee, claiming that he had no prior knowledge of the break-in. But in 1975, he was found guilty of conspiracy, obstruction of justice and perjury. He was sentenced to two and a half to eight years in prison and he was disbarred from practicing law in New York.
Estranged from Martha, John ended up serving 19 months of his sentence before being released on parole for medical reasons. In 1988, 13 years after he was found guilty, he suffered a heart attack on a sidewalk in Washington D.C. and died.
New episodes of Gaslit drop every week on Stan, login or sign up here.
