Director Steven Spielberg has announced that plot details of the fourth Indiana Jones movie will be revealed throughout the film itself.

Since Indiana Jones and the Kingdom of the Crystal Skull went into production, LucasFilm has insisted on keeping the plot a secret.

But due to huge demands for movie spoilers, Spielberg said he wanted to give Indy fans what they wanted.

"Yeah we had hoped to keep quiet on the matter", said Spielberg. "But after millions of forum members and bloggers became so desperate to find out Indy 4's storyline, I thought it would be best to reveal it to the world in movie theatres".

Movie purists are outraged at the decision, with some arguing that the movie-going experience will ruined if plot details are leaked.

"I'm surprised George Lucas has allowed this to happen," said one critic. "After all, he's usually so good about safe-guarding story lines. I mean the plot to the new Star Wars trilogy is still a huge mystery".