Bodybuilding icon and two-time Mr. Olympia Franco Columbu died on Friday after apparently drowning at sea, according to multiple reports in his native Italy. Columbu was 78.

La Nuova, an Italian media outlet, said Columbu drowned while swimming at a beach in San Teodoro in Sardinia.

Arnold Schwarzenegger, a close friend and training partner of Columbu’s, wrote on the blog website Medium that the Italian bodybuilder was his partner in crime and that he is grateful for the 54 years of friendship the two shared. “I am devastated today,” the seven-time Mr. Olympia wrote of Columbu. “My life was more fun, more colorful, and more complete because of you.”

Columbu was crowned Mr. Olympia in 1976 and 1981, and won the now defunct lightweight category from 1974-76.

Know as “The Sardinian Strongman,” Columbu was also well-known for his strength, having PRs that included a 750-pound deadlift, 665-pound squat, 525-pound bench press and 400-pound clean and jerk. He also participated on television’s World’s Strongest Man competition during the 1970s.

He and Schwarzenegger met in Germany back in the 1960s, and the two trained together and became inseparable. Columbu was Arnold’s best man when he married Maria Shriver in 1986.

Columbu had small roles in many of Arnold’s movies, including roles in Conan the Barbarian, The Terminator. He also appeared in the bodybuilding classic Pumping Iron.

He was a licensed chiropractor, and in 2006 was appointed to the California Board of Chiropractic Examiners by then-Governor Schwarzenegger.

This is a developing story, and it will be updated as more details become available.