"There's an old saying, 'Never meet your heroes'," the 'Terminator' star wrote on Twitter, posting a photo of himself with the last leader of the Soviet Union.

"I think that's some of the worst advice I've ever heard. Mikhail Gorbachev was one of my heroes, and it was an honor and a joy to meet him," Schwarzenegger added.

"I was unbelievably lucky to call him a friend. All of us can learn from his fantastic life."

The two knew each other for "a long time", according to the Gorbachev Foundation, and the Austrian-born Schwarzenegger once visited the former leader in Moscow, reports independent.co.uk.

Gorbachev died on Tuesday from "after a serious and long illness", the Central Clinical Hospital in Moscow said, quoted by Russian news agencies.