Olympian Michael Phelps announced the death of his father, Fred, in an Instagram post Monday.
"You'll always be my dad…And I'll always be your son," Phelps wrote. "…Love you dad and I will miss you❤️❤️ rip dad."
Fellow athletes Lindsey Vonn, CC Sabathia and Adam Jones were among those who offered condolences in the Instagram comments.
As TMZ Sports noted, Fred Phelps played college football and tried out for the Washington football team. He later became a Maryland State Trooper.
Michael Phelps is the most decorated Olympian of all-time, winning 28 medals in swimming, including 23 gold medals. He retired after the 2016 Olympics.