Schwarzenegger's 'Best Friend' Franco Columbu Drowns at 78

Franco Columbu, a world-renowned bodybuilder who parlayed his success into an acting career, drowned Friday off the coast of his native Sardinia after suffering a heart attack while swimming, THR reports. He was 78.

Columbu, a frequent World's Strongest Man competitor, was Mr. Universe 1970 and Mr. Olympia 1976 & 1981.

Among his film work, which kicked off with a bit part in 1976's "Stay Hungry," he was most famous for an appearance as himself — lifting a car in 1977's "Pumping Iron."

He went on to work in a number of other TV and film projects, including several with his friend of over 50 years, Arnold Schwarzenegger: "Conan the Barbarian" (1982), "The Terminator" (1984), and "The Running Man" (1987).

He also worked in Italian films and as a chiropractor.

A grieving Schwarzenegger tweeted, "I love you Franco. I will always remember the joy you brought to my life, the advices you gave me, and the twinkle in your eye that never disappeared. You were my best friend."