The star was even able to evade semi-traditional physical examinations by doctors before filming, as large studios often forgo the process, a film finance lawyer told The Hollywod Reporter.
Studio head Kevin Feige was sent an email with limited information within an hour of the star's death but by the time Feige read the memo, the actor had died.
Breaking my twitter silence to share some beauty. This was one of my final texts from the brilliant & once-in-lifetime talent, @chadwickboseman - take this in & celebrate life. He knew how precious every moment was. Tonight the Heavens received one of its most powerful angels. pic.twitter.com/Hj8Cb1IfZS
The Hollywood Reporter has said a source close to the actor thought he had beaten cancer and would be back in time to star in "Black Panther II".
The actor only found out how serious his condition was a week or so before he died.
Only a few people close to Boseman knew about his poor health, including Logan Coles his producing partner, his agent, trainer and Brian Helgeland, the director of "42", the film which launched his career.
