Don Grady, who was one of television's most beloved big brothers as Robbie Douglas on the long-running 1960s hit My Three Sons, died Wednesday.
He was 68.
His My Three Sons co-star Barry Livingston, who played youngest brother Ernie, confirmed Grady's death to The Associated Press late Wednesday.
Livingston said Grady suffered from cancer and received hospice care at his home in Thousand Oaks, Calif. The exact cause of death is unknown.
"It's the oldest cliche in the world when TV brothers refer to each other like biological brothers, but he was the oldest, and somebody I looked up to and learned from a great deal about life," Livingston said of his late co-star.
Born in San Diego as Don Louis Agrati, young Don Grady had a brief stint singing and dancing on The Mickey Mouse Club starting at age 13.
But he was best known by far as one of Fred MacMurray's My Three Sons on the series that ran on ABC and later CBS from 1960-1972.
The popular show was among the longest running sitcoms of all time with 380 episodes.