Russell Crowe was reluctant to portray disgraced TV mogul Roger Ailes onscreen because there was nothing appealing about his reputation as the head of Fox News.

The Gladiator star's knowledge of Ailes' background was largely limited to the latter part of his life, including his resignation from the right-wing cable news network in 2016 amid allegations of sexual misconduct, and his death in 2017, aged 77, but it was only when he decided to give the script for The Loudest Voice a chance that he discovered there was so much more material he could work with.

"I didn't think I was interested in (playing) Roger Ailes," Crowe admitted on U.S. breakfast show Today. "I knew him from the frame of Fox News, and I probably knew about (him) being an advisor to three presidents, but that was really all I knew."

"It was the quality of the writing that made me then start to look into who Ailes was," he continued, "and then to find out that he was the executive producer of The Mike Douglas Show (1960s U.S. talk show) at the age of 26, that he'd risen already to a position that was quite powerful in television, when television was still really relatively new... I was like, 'Who is this guy? This guy is like a soothsayer, he can see the future.'"

The Loudest Voice, which focuses on the last 10 years of Ailes' life, boasts an all-star cast, with Crowe joined by Sienna Miller, Seth MacFarlane, Annabelle Wallis, and Naomi Watts, among others.

The limited series, based on Gabriel Sherman's bestselling book The Loudest Voice in the Room, debuts in the U.S. on Sunday (30Jun19).

It's not the only new project about Ailes - director Jay Roach is also developing a biopic about the producer, with John Lithgow as Ailes, alongside Nicole Kidman, Margot Robbie, Charlize Theron, and Malcolm McDowell as Rupert Murdoch.