Ryan Coogler is remembering the special moments he got to experience with Chadwick Boseman.

The Black Panther director shared a moving tribute, which was sent to E! News, to celebrate the life and legacy of the actor. Coogler’s heartfelt letter comes only a few days following the news that Boseman had passed away.

On Friday, Aug. 28, the actor died at the age of 43 after privately battling colon cancer for four years. Just like the rest of the world, Coogler said he was surprised to learn about Boseman’s diagnosis.

“After his family released their statement, I realized that he was living with his illness the entire time I knew him,” the director penned, adding, “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,” Coogler continued. “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.”

Coogler remembered the early process of Black Panther, and how he inherited Boseman, who was previously cast to appear in Captain America: Civil War.

However, the casting couldn’t have been better, because according to Coogler, Boseman impressed him after deciding to make the African language of Xhosa the superhero’s native tongue. Boseman learned the lines in Xhosa on the spot, Coolger recalled.

“Even though I hadn’t met Chad, I was already in awe of his capacity as actor,” he wrote in part. “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.”