(Cover) - EN Showbiz - James Francos gruesome amputation scene in his new movie caused cinemagoers to cry and pass out.

The 32-year-old Hollywood actor stars in 127 Hours, a film about American mountain climber Aron Ralston who was forced to cut off his own arm when it became trapped under a boulder near Moab, Utah, in May 2003.

Aron, 34, had been climbing in Blue John Canyon when a boulder became dislodged and pinned him to a canyon wall. He spent five days trying to free himself before realising his attempts were futile.

The scene in which the operation takes place had a heavy impact on people who attended a recent screening of the film.

One viewer passed out during the amputation scene and others sobbed, while Ralston said he cried the whole time that his character was stuck in the canyon, the New York Post reported.

James, who has also starred in Spider-Man and Pineapple Express, took great pains to get to grip with the character he would be playing in the intense cinematic role.

During conversations with Aron, James asked him to describe exactly what it felt like to carry out the unimaginable and bludgeon your own arm.

At a screening of 127 Hours hosted by Vanity Fair Editor Graydon Carter, Franco told the crowd that Ralston told him cutting his arm felt like shoving your entire arm in molten lava, the newspaper said.

The scene is drawn out because the task took 45 minutes to conduct in reality, and the producers wanted to effectively re-create what it was like for brave Aron without scrimping on the gory details.

It is a controversial decision which James admires and believes is the right one.

The whole idea of the film is you enter the journey with him and you don't cut away to a lot of people looking for him, he told MTV News recently. It's an immersive experience, and it's cathartic when he does it because it's a relief for everyone and a triumph in some way as well. (C) Cover Media