Sylvester Stallone’s real life father, Frank Stallone, has a cameo playing the man who rings the opening bell of the Creed vs. Balboa fight. Sylvester’s younger brother, also has a cameo playing the lead singer of the street band! Keeping it in the family! “YO, ADRIAAAAAN”!!…Check this out…The movie’s line “Yo, Adrian.” was voted as the #80 (out of 100) movie quote by the American Film Institute!