During the filming of the famous "Mouth of Truth" scene in Roman Holiday, Gregory Peck played a practical joke on his unsuspecting co-star Audrey Hepburn. He hid his hand up his sleeve after putting it in the statue's mouth, making her believe it had been bitten off, resulting in her genuine scream of surprise that was kept in the final film. Credit: Paramount Pictures | History In Pictures

Audrey Hepburn in My Fair Lady (1964) - 12 Days of Audrey