LONDON: James Cameron reshot a scene of his "Titanic" 3D venture after an astronomer pointed out that the stars were in the wrong place as the ship sank.

It involved a scene showing Rose lying on a piece of driftwood after American astronomer Neil deGrasse Tyson sent him a "snarky" email.

Tyson said the original film had a wrong star field for the time and date, 4.20 a.m. on April 15, 1912, which Cameron should have known better.

Cameron challenged him to send the exact star map and has now included it in the relaunched 3D version of the blockbuster film, the Telegraph reported.

"So I said ‘All right, send me the right stars for that exact time and I’ll put it in the movie,’" said Cameron, which Tyson obviously did.

It is the only major technical change to the drama, which will hit British cinemas Friday.