Lady Gaga Details Her Harley Quinn Transformation for Joker: Folie à Deux

The  JokerFolieàJoker met his match at Arkham State Hospital thanks to Lady Gaga.

The "Just Dance" singer gave insight into her process of becoming Harley Quinn for Joker: Folie à Deux and what it really took to become the villain.

"I allowed myself, once I found her voice, to make her whatever I wanted at any given moment—whatever the scene or the moment called for," Gaga told E! News correspondent Will Marfuggi. "There're moments on the phone where the music is fantasy or it's Arthur's dream. So, in those moments, I thought, 'OK, what would Arthur need right now?' Maybe Arthur needed her to be amazing." 

After all, Harley, who finds love in Arthur Fleck, aka The Joker (Joaquin Phoenix), ultimately becomes his sidekick as the two unleash chaos in Gotham through their linked insanity. But finding her voice for the film, which premieres in theaters Oct. 4, meant learning to sing in a very different way.

"I allowed it all to become available to me once I really honed in on trying to sing as her without technique, without the right breathing, just really naked and bare," she continued. "At first, it was really scary and it felt really unnatural, but then it felt completely natural for her. That was exciting. I remember when I first saw it back on camera, and I felt like, 'OK, I think I found something authentic.'" (For more with Gaga, tune into E! News Monday, Sept. 23 at 11 p.m.)

But for the A Star is Born actress, it wasn't always easy leaving Gotham at the end of the night when she was back home with her fiancé Michael Polansky, but she knew it was important to do so.

"I always tried every night that I went home to leave Harley at work," Gaga explained. "We would make dinner every night after filming. I tried for sure. But sometimes, the darkness of the movie would stay with me, or sometimes the scene can stay with you. The character tries to creep in all serious ways, but I really tried to drop it."

Although she quipped, "Some people would love to hang out with Harley."

Gaga previously shared the ways in which portraying the Gotham supervillain—which she's said was something that took months and was "a very introspective" experience—inspired her to take a break from social media during filming, during which time she was able to reconnect with her inspiration.

"I've been experiencing my creativity ever since last summer in a really special and private way," she wrote in June. "I can say for the first time in many years that my love of making art, music, fashion, and supporting community has never been more fulfilling."

"I hope you know this time to myself has been extremely healing and recharging for my heart, mind, body, and creativity—to create within myself and to have a personal life that's just for me," she added. "I can't WAIT for you to experience it."