While training, Adonis wears a shirt with the message "Why do I wanna fight? Because I can't sing and dance..." This was a line from Rocky to Adrian on their ice skating date in the first Rocky (1976).
Just as the film was entering pre-production, Sylvester Stallone's oldest son Sage Stallone died of a heart attack. Stallone has admitted that the loss almost sent him into a full breakdown, but Ryan Coogler was eventually able to convince him to use the film as a dedication to Sage, focusing specifically on the father-son relationships that appear in it. Although initially resistant, Stallone said at the Golden Globes that Creed helped him cope with Sage's death.
Carl Weathers, who played Apollo Creed, gave his strong endorsement to the movie and Michael B. Jordan's performance. Jordan felt extremely honored.
Sylvester Stallone requested that Michael B. Jordan wear the famous American flag trunks that Apollo Creed wore in Rocky (1976) and Rocky wore in Rocky III : L'Œil du tigre (1982) and Rocky IV (1985) to keep tradition in the "Rocky" universe.