While promoting Sr. on Armchair Expert with Dax Shepard and Monica Padman, Robert Downey Jr. opened up about the gritty details of his life in prison and his struggle with addiction. Sr. is the documentary film of RDJ's father, per TooFab.

The conversation opened with addiction, which is something both Dax Shepard and Robert Downey Jr. have in common: “[When] you discovered drugs, you were like, ‘Yes, what a joke, this is hilarious. Now I feel like a cartoon character. Now I'm really getting one over on the universe. I'm having a blast in this technicolor, kaleidoscopic dream of mine.' And then it catches up with you because again, it's a f*****g tragedy.”

As recovering addicts, both Shepard and RDJ experience addictive tendencies in similar ways, a sort of neuroticism. That personality trait doesn't disappear even in recovery. They also discussed addiction as a nature versus nurture issue, and based on the film Sr., RDJ's addiction “is more based in life or his youth.”

He then detailed the center he was sentenced to: “Arguably the most dangerous place I've ever been in my life because nobody is designated if they're a level 1, 2, 3, or 4 criminal,” he said.

“There was no opportunity there; it was only threats: yes, everyone is going to take your wallet so watch it,” he said. “I remember walking out at one point when I popped out of my cell to go to the shower, and I didn't know it but I was a little spun out and I had my underwear on backwards that put the entry in the back. I remember eliciting some strong chuckles and jeers from my fellow inmates.”