Christian Bale says he felt that gruff Batman voice was a necessity to go with the costume.
Bale took on the role Batman in Batman Begins, The Dark Knight and The Dark Knight Rises as he teamed up with director Christopher Nolan.
Speaking to MTV News the actor said: "I got there. They put me in [former Batman] Val Kilmer's suit. It didn't even fit properly and I stood in it and I went, 'I feel like an idiot.'
"What kind of guy walks around dressed like a bat, and is then going to go, 'Hello, how are you? Just ignore that I'm dressed as a bat.'
"I went 'I can't do this in a normal voice. I have to become a beast in order to sell this to myself.'"
Bale's Batman movie became a billion dollar franchise, but he left the role last summer.
Ben Affleck will take over the part for Batman vs Superman and Bale says that it is important that the actor finds his own voice.
"The voice ain't for everybody. Ben's obviously going to have to do his own thing, but it was the only way that I could find how to get into that and to justify wearing the fricking Batsuit."
Bale will be back on the big screen in American Hustle in the new year - a film that sees him reunite with director David O'Russell.
He has also completed work on Out of the Furnace, Knight of Cups and an untitled Terrence Malick movie.
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