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 on Sunday night (20.01.13), 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 all-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.''