Christian Bale auditioned for 'Batman Begins' wearing Val Kilmer's Batman costume.

The actor, who starred in Christopher Nolan's smash hit 'The Dark Knight' trilogy, originally auditioned for the part while sporting the 'Batsuit' worn by Kilmer in 1995's 'Batman Forever', a new documentary reveals.

All of the actors who met with Nolan for the part in 2005's Batman reboot wore the Kilmer costume, despite a later incarnation worn by George Clooney in 1997's 'Batman and Robin' also being available. However, Clooney's costume - and the movie itself - has often been the subject of ridicule.

The behind-the-scenes documentary about the making of the Batman films can be found on a new collector's edition home release of 'The Dark Knight' trilogy and features footage of Bale's audition with Amy Adams, who read for the part of Rachel Dawes, played by Katie Holmes in the first film and Maggie Gyllenhaal in 2008's 'The Dark Knight'.

Nolan explained that he had actors put on Kilmer's suit to see if they could ''project massive energy through this costume''.

The director also said on the documentary he was impressed by Bale's gruff voice as Batman in his audition.

He said: ''I think Christian's voice was a big part of the impression he made in the test. He had decided that Batman needed to have a different voice to Bruce Wayne, that he needed to put on a voice.''