John Madden's unexpected death shakes up NFL world

John Madden's death on Tuesday appeared to resonate with several celebrities, sports figures and entertainers as they took to social media to remember the legendary head coach and face of the "Madden NFL" video game franchise.

Madden, whose cause of death was not immediately revealed, died at the age of 85. He rose to fame as coach of the Oakland Raiders, making it to seven AFC title games and winning the Super Bowl after the 1976 season.

"John Madden is the greatest, and most influential, sports broadcaster of all time," political commentator and sports journalist Clay Travis wrote in a tweet. "An absolute legend of sports, people will be playing the video game named after him generations to come. RIP."