Matt Damon is no stranger to being lost on an alien planet. It happened to him in The Martian and Interstellar. And as it turns out, it almost happened to him in what was until very recently the highest-grossing movie of all time: Avatar, which almost had Damon as its lead instead of Sam Worthington as Jake Sully.

Talking about the whole incident during an interview with British GQ, Damon revealed that James Cameron himself had come to him with the part, and offered him ten percent of the film's profits if he were to take the role.

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"Jim Cameron offered me Avatar. And when he offered it to me, he goes, 'Now, listen. I don't need anybody. I don't need a name for this, a named actor. If you don't take this, I'm going to find an unknown actor and give it to him, because the movie doesn't really need you. But if you take the part, I'll give you ten per cent of...' So, on the subject of money..."

Since Avatar ended up grossing over 2.8 billion dollars at the box office, the actor missed out on a staggering 250 million+ dollar paycheck when he passed on the role. This would make not doing the film one of the biggest missed opportunities in Hollywood history, a fact that Damon himself is acutely aware of.

"I told John Krasinski this story when we were writing Promised Land. We're writing this movie about fracking. We're writing in the kitchen and we're on a break and I tell him the story and he goes, 'What?' And he stands up and he starts pacing in the kitchen. He goes, 'OK. OK. OK. OK. OK.' He goes, 'If you had done that movie, nothing in your life would be different. Nothing in your life would be different at all. Except that, right now, we would be having this conversation in space.' So, yeah. I've left more money on the table than any actor actually."

In case you're wondering what made Damon turn down the part, it turns out it all came down to a question of prioritizing working James Cameron below wanting to collaborate with longtime friend and filmmaker Paul Greengrass on the Jason Bourne series.

"I mean, the bigger thing still to this day, my bigger regret is - it would have caused a problem for Paul Greengrass and for all my friends on The Bourne Ultimatum, so I couldn't do it. But Cameron said to me in the course of that conversation, 'Well, you know, I've only made six movies.' I didn't realize that. He works so infrequently, but his movies, you know all of them. So it feels like he's made more than he has. I realized in having to say no that I was probably passing on the chance to ever work with him. So that sucked and that's still brutal. But my kids are all eating. I'm doing OK."

For a guy who has only made six movies so far, James Cameron has had an outrageously successful profit ratio on all his ventures. With many critics finding Worthington's lead performance in Avatar quite bland, it is possible to see that Damon with his easy-going, everyman charm and action hero chops might have been better suited to the role of Jake Sully. But the fact that Avatar did not have Matt Damon in the lead ultimately did nothing to affect its unheard-of success at the box-office.

Damon himself, while missing out on Avatar, went on to star in several critically and commercially successful films. The biggest loss might be for the audience, who missed out on Cameron's most significant collaboration with a star actor since Leonardo DiCaprio in Titanic.