Leto: Dresses made me feel womanly
The actor-rocker had to don dresses and make-up to portray transgendered Aids patient Rayon in the real-life drama. His commitment paid off as he is up for a best supporting actor Oscar and has already won Golden Globe and Screen Actors Guild gongs.
"Well, I didn't discover a new hobby," he joked.
"But I did appreciate how it changed me in how it made me move differently and behave differently. I could see how Rayon appreciated it and how it made her feel beautiful."
The 42-year-old added: "The heels are fine but tights are really difficult to wear."
Jared - who embarked on a full waxing regime, removing all the hair on his body and even his eyebrows - joked: "It was a very transformative role."
Dallas Buyers Club is his first role in a while and he revealed he agreed to it because it was "special".
"It was almost six years since I made a film and I decided to sign up to this because it was so special. I fell in love with the director, the cast and the script and thought this would be a wonderful way to return to the screen. I'm glad I did it," he said.
"I never thought about awards, but it's certainly a celebration not just of my performance, but it is a tribute to this beautiful community of brave souls and Rayons of the world, and to the people out there living with HIV and Aids, the people who have struggled and fought for their lives."
:: Dallas Buyers Club is released on February 7.