Boseman, 43, died of stage 4 colon cancer late last month.
He received cancer treatment while filming Black Panther. Boseman’s mother said he concealed his cancer diagnosis from friends and fans because he didn’t want anyone fussing over him.
Nyong’o, 37, said Boseman’s passing has been a “gut punch every morning.”
The ’12 Years a Slave’ Oscar winner said Boseman’s “immortal energy” will never die.
“I am aware that we are all mortal, but you come across some people in life that possess an immortal energy, that seem like they have existed before, that are exactly where they are supposed to always be—here! That seem ageless,” she wrote on social media. “Chadwick was one of those people.”
Nyong’o said Boseman had a “profound effect” on her and his “higher frequency” resonated on the set of the Marvel film.
“I remember being struck by his quiet, powerful presence. He had no airs about him, but there was a higher frequency that he seemed to operate from.”
She concluded by asking others not to waste time and to cherish every moment on earth.
“Chadwick’s death is something that I can neither take in nor take in my stride right now,” she wrote. “Perhaps with time. I’m going to take my time and in his honor, I promise not to waste my time. I hope you will do the same.”
Early warning signs of colon cancer include:
- Changes in bowel habits
- Feeling of incomplete bowel movement
- Abdominal cramping
- Low-grade fever (under 101.5)
- Weakness and fatigue
- Blood in stool
- Pencil thin stools