Credit: Alberto E. Rodriguez/WireImage

Rocky actor Tony Burton appeared in six of the seven movies, training against and alongside the titular boxer. After Burton died at 78 on Thursday, Sylvester Stallone mourned the man who played Duke.

Stallone shared a photo of him and Burton during Rocky IV on Friday. “Tony Burton who played the character of Duke brilliantly in all six Rocky movies… Rest in peace,” he writes.

Burton appeared as the ace boxing trainer each of the franchise’s movies save last November’s Creed.

Fellow Rocky actor Carl Weathers recognized Burton’s death with a tweet Thursday. “Sad news. RIP Tony Burton. His intensity and talent helped make the Rocky movies successful,” he wrote.

Stallone is nominated for Best Supporting Actor at Sunday’s Oscars for his most recent portrayal of Rocky in Creed.