Actor Jonah Hill's preparation for Martin Scorsese's new movie The Wolf Of Wall Street included learning how to speak while wearing prosthetic teeth.

The 21 Jump Street star had to practice talking for a month before shooting the film to make sure he could be understood when filming began.

He tells U.S. breakfast show Good Morning America, "It was interesting because I had to learn how to re-talk again because I had such a horrible lisp when I put them on... I would rehearse with them in and I would just also make phone calls all the time with the teeth in, so I could lose my lisp and also do the strange accent... So I would just stay on the phone for as much as I could..."

In the film, Hill plays Donnie Azoff, a character based on Daniel Porush, who was convicted of securities fraud and money laundering.

The Wolf Of Wall Street stars Leonardo DiCaprio as real-life stockbroker Jordan Belfort, who served 22 months in prison for stock market manipulation.

The movie hits theatres in the Us. on Christmas Day (25Dec13).