Angelina Jolie "nearly passed out" when she first performed opera in preparation for 'Maria'.
The 49-year-old actress portrays soprano Maria Callas in the biopic and revealed that it gave her a sense of appreciation for the skill needed to perform opera.
Angelina told Empire magazine: "I am now a huge fan of opera – I listen to it more than most other kinds of music. I started singing classes and Italian classes, but when I switched to opera classes it was a whole other universe, and it required something very different.
"The first time I really sang, for the first few classes, I nearly passed out every time. I couldn't quite get my breathwork. I think that's why it takes a lifetime of training to really do it."
The movie is set during the final years of Callas' dramatic life during the 1970s and Jolie believes that the story can be enjoyed by those with little knowledge of opera.
She said: "Something really cool about the film is that if you don't know opera, you can go through the entire journey of the film and understand it.
"If you do know opera, you understand why certain pieces of music and certain arias come at certain times. It adds many extra layers. That's an artist's life, to say, 'What were all these different world that I walked in, and how did these worlds colour my life and change my perception?'"
Jolie revealed that she enjoyed getting to wear a mixture of glamour and homely outfits as her alter ego in Pablo Larrain's picture.
The 'Lara Croft: Tomb Raider' star said: "What's interesting to me is that there was this public Maria who was a very stylish woman of her time. It's some of the best fashion you've seen.
"But for me the balance of that was at home, in her robe and her glasses. There's this hand-knitted robe that was crocheted in Italy. I felt that taste of this Greek woman, who had this earthy quality to her at home in her fifties. She was stripped down there. That was her loving who she is."
Angelina previously confessed that she was "terrified" to take on the role of the iconic opera singer.
She told The Hollywood Reporter: "I was terrified. Pablo was very clear that if I tried my best, he would support my process and help me. He helped by scheduling the most intimate moments first and high-pressure toward the end. … He treated me like a singer, and it meant the world that he believed I could do it.
"Pablo had a coach with me the entirety of the film and classes nightly after shooting."
