Black Panther director Ryan Coogler penned a powerful tribute to honor the late Chadwick Boseman, Sunday. Coogler says he did not know of Boseman's illness prior to his death.

Ryan Coogler, Chadwick BosemanVivien Killilea / Getty Images

Coogler's letter, published in Deadline, begins with condolences to Boseman's family and a story about the first time he met the late actor.

"I noticed then that Chad was an anomaly. He was calm. Assured. Constantly studying. But also kind, comforting, had the warmest laugh in the world, and eyes that seen much beyond his years, but could still sparkle like a child seeing something for the first time."

Boseman's family announced that the Black Panther star died Friday, after a four-year-long battle with colon cancer. He was 43-years-old.

"Chad deeply valued his privacy, and I wasn’t privy to the details of his illness," Coogler continued. "After his family released their statement, I realized that he was living with his illness the entire time I knew him. Because he was a caretaker, a leader, and a man of faith, dignity and pride, he shielded his collaborators from his suffering. He lived a beautiful life. And he made great art. Day after day, year after year. That was who he was. He was an epic firework display. I will tell stories about being there for some of the brilliant sparks till the end of my days. What an incredible mark he’s left for us."

Black Panther is airing on multiple channels this weekend in honor of Boseman.