James Cameron has admitted re-shooting a 'Titanic' scene for the 3D version of the film.

The director re-filmed a section of the movie - which starred Leonardo Dicaprio, Cathy Bates and Billy Zane - that saw Kate Winslet's character Rose holding onto a piece of debris from the wreckage of the singing ship in an attempt to survive.

James decided to re-do the scene after he was sent a ''snarky'' email from US astronomer Neil de Grasse Tyson, who told the helmer that Rose wouldn't have been able to see the specific star field depicted in the movie in 1912, when the film is set.

James told USA Today: ''With my reputation as a perfectionist, I should have known that and I should have put the right star field in. So I said 'All right, send me the right stars for that exact time and I'll put it in the movie'.''