Penn takes a few shots at Donald Trump's former advisor.
The actor-turned-director-turned-novelist told Conan O'Brien in an interview that aired Thursday night that he thought Bannon -- who produced Penn's 1991 directorial debut "The Indian Runner" -- was "a crook."
"That was my first sense of him, that he was, other than the C-word charming, he was a crook, I think is what I thought," Penn bluntly explained.
Where as many might not know that Bannon worked in entertainment before becoming a political icon as one of the masterminds behind Trump's presidential campaign, Penn wasn't aware that his former producer was the same guy working for the president.
"I didn't even know it was the same Steve Bannon until I looked at him closely and imagined the Steve Bannon I knew," Penn said. "But where the toxins of the soul so deteriorate and bloat and weld into this —- I don't think you can age like that without hating people. So that's my impression of him."
Penn, who visited the late-night talk show to promote his new, poorly reviewed novel "Bob Honey Who Just Does Stuff," also insinuated Bannon may have misappropriated the film's budget to hire unnecessary "cheerleader-looking new makeup assistants."
When Conan asked if the newly hired assistants did a good job, Penn sarcastically replied, "Oh, I mean, every bit as good as most of the people in the West Wing today."