James Cameron has written a letter to Chinese audiences to draw them into theaters to see his latest film, Sanctum.

"Sanctum is a 3D adventure that takes you to the depths of the Earth, where a group of explorers is trapped deep underground when a violent storm floods their cave," he says in an open letter provided by Edko Films, the film's mainland distributor.

"We filmed Sanctum using the same Fusion 3D cameras that were used on Avatar. You will feel the cave surrounding you, and be pulled into the story along with the characters."

The film was released at mainland theaters on Sept 9.

Cameron's Avatar raked in 1.3 billion yuan ($204 million) in China and is the highest-grossing film in the country.