Helena Bonham Carter read books on prostitution to prepare for her role in 'The Lone Ranger'.

The 'Les Miserables' actress plays a prosthetic leg-wearing working girl in the western film - which stars Armie Hammer in the title role and Johnny Depp as his sidekick Tonto - and she studied the illicit trade to research her part.

Speaking to BANG Showbiz at the London Critics' Circle Film Awards at the Mayfair Hotel, she said: 'I play a peg-legged whore ... a madam. Inside my peg-leg, I got a gun. That was really good fun. That was the best prop I've ever had.'

When quizzed how she prepared for the role, the 46-year-old star earned laughs by joking that she 'got into prostitution', before adding: 'Last year was great. I had books on prostitution on my kitchen table, and books on pick-pocketing, and books on entomology. I played an entomologist. I read up on prostitution. I didn't do any field trips, though.'

The Oscar-nominated actress was excited to reunite with her 'Dark Shadows' and 'Sweeney Todd' co-star Depp, but wasn't sure if it was really him when they first met on the film's set because his face was covered in white make-up for his role as the Native American spirit warrior.

She explained: 'It's always fun with him because you never know what he's going to come as. It's like, 'Oh, OK'. He's completely unrecognisable. He's got 'cracker-face' make-up all over him. In fact, the first day he looked 120. It might not have been him for all I know.'