The Australian star’s epic film depicting William Wallace’s ill-fated rebellion against the English won five Oscars.
But now he says he was lucky to escape alive after he was pulled free by a stuntman from under a horse which had toppled backwards and was about to land on him while shooting a battle scene.
In an Empire movie magazine interview ahead of the film’s Blu-Ray re-release this month, Gibson said he was forced to “fire” the horse, one of hundreds used in filming, admitting it “nearly killed me”.
He added: “He had a good trick where he did this whole rear-up thing, but he’d also fall backwards, which is a problem if you’ve fallen off first and you’re behind him.
“He did that to me. It’s actually on film – I must find the footage! My stunt double ran in and pulled me out of the way just as the horse fell.”
Braveheart was released in 1995 after its premiere at Stirling Castle and became a box office-smash, winning a clutch of Academy Awards, including best director for Gibson and best picture. However, it has divided critics over the years, partly because of various historical inaccuracies.
The screenplay was penned by American Randall Wallace, who found inspiration from the statue of Wallace at Edinburgh Castle during a trip to research his roots. He based much of the script on a 15th century poem about Wallace, who was hanged, drawn and quartered after being found guilty of treason.
Gibson said: “It was given to me initially as a project to just act in, but it just kept asserting itself in my thoughts.
“My career was hopping. There was a lot of noise. Braveheart was like a radio coming into reception. I’d be lying in bed constructing shot lists for it before I went to sleep.
“It was like someone had come up to me with a big fish and slapped me across the face with it and said: ‘You have to direct this.’”
He also disclosed extras from the Irish army had to change sides during the shoot, when parts of Kildare and Wicklow stood in for the Highlands. He said: “One day they were all dressed like Scots and the next they’d be English.”
But he credited his accent in the film to locals he met in Fort William during a six-week shoot in the area. He also revealed animal rights activists suspected horses were mistreated during filming. He said: “It was kind of flattering. I had to show them some behind-the-scenes footage. We constructed dummy horses on air jacks that you could do awful things to. So that was cool.”
He added: “I’ve thought about an extended version but I don’t think I want to put it out there. It’s aged well. It still works. We did things that were kind of amazing.”