Around 54 minutes into James Cameron’s 1997 film Titanic, the camera pulls back to reveal the vast expanse of the North Atlantic, and Kate Winslet’s Rose asks Leonardo DiCaprio’s Jack, “Why can’t I be like you, Jack? Just head out for the horizon whenever I feel like it?”

Except it’s not Leo. It’s his Titanic photo double, 29-year-old jobbing actor Brett Baker.

If there’s a shot in the film where you see Jack, but not his face—just his bohemian flop of hair, the back of his head, his shoulder, maybe his backside—there’s a good chance that it’s not actually DiCaprio, but Baker: the film’s most low-tech special effect.

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