Michael B. Jordan’s portrayal of Erik Kilmonger was riveting, and he revealed the secret to his skills during a visit to The Late Show.

Jordan has collaborated with Black Panther director Ryan Coogler three times and the men have a special method for developing characters: journaling.

“What we usually do with our characters is we write a backstory. I write a journal,” he told Stephen Colbert. “I have journals or diaries or whatever for every character that I have, from the earliest memory to the first page of the script. And for me, it kind of gives you context.”

When Colbert pressed the “Creed” star about the contents of the journals, Jordan was reluctant to share. Dang.

“For him, his was particularly dark. It was a very sad journal. Not having his mom growing up, in and out of the system, foster homes and whatnot,” Jordan continued. “But it's a lot of dark stuff that's probably not right for television. But it was deep, man, and it allowed me to kind of go to that place right before a scene. It allowed me to lock in.”

Who else wants a Black Panther prequel using the stuff on those diaries?

Check out the full interview below: