The devastating news of Chadwick Boseman’s death last week was met with shock and disbelief from his fans and close friends alike. 

Black Panther director Ryan Coogler and Da 5 Bloods director Spike Lee have already said they had no idea Boseman was battling colon cancer, a disease he was diagnosed with in 2016. Marvel boss Kevin Feige reportedly only learned about Boseman’s diagnosis on the day he died.

Only a “tight-knit” circle of friends and his team were aware of the actor’s diagnosis, according to The Hollywood Reporter. Michael Greene, Boseman’s longtime agent, was one of those people, and he explained Boseman’s reasoning for not telling more people.

Greene told THR that he partly attributes Boseman’s choice to keep his cancer battle private to lessons the actor learned from his mother, Carolyn.

″[She] always taught him not to have people fuss over him,” explained Greene. “He also felt in this business that people trip out about things, and he was a very, very private person.”

Keeping his health battle to himself meant that Boseman struggled privately. Greene talked about Netflix’s upcoming movie Ma Rainey’s Black Bottom, based on the play written by August Wilson, explaining that though Boseman was experiencing “hard-core pain” during filming, he was excited to be in a movie produced by Denzel Washington and “launch this cycle of August Wilson at Netflix.”

In the wake of Boseman’s death, fans and friends, including Washington, have continued to offer heartfelt tributes. Many have flooded social media with the “Wakanda Forever” salute, which Boseman made famous in “Black Panther.”