Franco Harris, the former Pittsburgh Steelers running back and four-time Super Bowl champion, has died aged 72.
News of his death came three days before his number 32 shirt number was to be retired.
The Pro Football Hall of Fame inductee, a nine-time Pro Bowl honouree, was the 13th overall pick in the 1972 NFL draft for the Pennsylvania outfit.
Over the following decade, he helped the Steelers to the game's biggest prize on four separate occasions, while he was named the MVP of Super Bowl IX.
Hall of Fame president Jim Porter said: "The entire team at the Pro Football Hall of Fame is immensely saddened today.
"We have lost an incredible football player, an incredible ambassador to the Hall and, most importantly, we have lost one of the finest gentlemen anyone will ever meet. Franco not only impacted the game of football, but he also affected the lives of many, many people in profoundly positive ways.
"The Hall of Fame and historians everywhere will tell Franco's football story forever. His life story can never be told fully, however, without including his greatness off the field.
"My heart and prayers go out to his wife, Dana, an equally incredible person, a special friend to the Hall and someone who cares so deeply for Franco's Hall of Fame teammates."
Having rushed for over 11,000 yards, Harris was the Steelers' leader in franchise history, and he was due to become just the third player to have their shirt number retired this weekend.
The Steelers had intended for the honour to coincide with the 50th anniversary of the Immaculate Reception, the match-winning play Harris was involved in for their first ever playoff win.
The running back famously was the apparently unintended receiver of Terry Bradshaw's last-gasp throw in the 1972 AFC divisional match with the Oakland Raiders, and ran for the clinching touchdown in the final minute.
Though the team subsequently lost their next match to the Miami Dolphins, the victory is widely regarded as an instrumental turning point that helped the club become the NFL's dominant force over the following decade.
Pittsburgh are due to face the now Las Vegas Raiders on Saturday, 50 years and a day since Harris had his magical moment.
Mike Tomlin's side are bottom of AFC North with a 6-8 record this season, and are looking to string back-to-back wins together for only the second time in 2022.