On October 11, 1991, during a break from rehearsals for The Royal Family, [Redd] Foxx suffered a heart attack on the set.
…
Foxx did his scripted part of the scene (walking across the back of a chair) while being livid, then immediately fell to the floor. Reese said that nobody initially suspected that anything was wrong, as Foxx was famous for Fred Sanford’s fake heart attacks on Sanford and Son and was particularly skilled at pratfalls. When he did not immediately rise, Reese went to the floor[38] and heard him say “get my wife” twice.[39] Reese called for paramedics.[39] According to Joshua Rich at Entertainment Weekly: “It was an end so ironic that for a brief moment castmates figured Foxx–whose 1970s TV character often faked coronaries–was kidding when he grabbed a chair and fell to the floor.”[40]

https://en.wikipedia.org/wiki/Redd_Foxx