The actress revealed which scene in the movie had the filmmakers worried for her.
During a conversation with Jake Gyllenhaal for Variety's "Actors on Actors" series, the 35-year-old singer and actress revealed why the filmmakers quickly called cut during one scene of the film, in which Gaga stars as Patrizia Reggiani, an Italian woman who marries a Gucci heir and then sets up his murder after he files for divorce.
"The way that I feel safe is just that I feel safe being in pain. I feel safe in art. I almost think I feel safer with art than I do in life," Gaga explained. "When I did the bathtub scene, when I went under, they had to yell 'Cut' because they were like, 'Get her out of there!'"
"I was fine. I can hold my breath for a long time. I’m a singer," she continued. "I feel protected by art. I feel art has saved me my whole life."
Gaga expanded on how acting has saved her earlier in the conversation, looking back on the days when she was "so mercilessly bullied" and had "really strict" parents.
"Acting for me was a way to totally escape who I was," she said. "And I think I’ve done it my whole career with taking on the artistic persona of whatever music I’m writing and living inside my art. And for films, it’s different, but it’s not."
In fact, Gaga said, when she's playing a character, she largely lives as that person even when the camera isn't rolling.
"When I’m in character, I don’t pretend we’re not filming," she said. "I get people who are like, 'Why did you keep your accent the whole time?' Can you imagine going in and out of that s**t all the time, and I would only get three takes? I had to be ready."
After House of Gucci wrapped filming, Gaga noted that she was able to escape her character more quickly than she has others in the past.
"I dropped her faster because she was a killer and there were some things about the transformation for me psychologically that were super challenging," she said. "When I watch the movie, it looks like I’m watching a montage of my life. I don’t feel like I’m watching a film."
When ET spoke with Gaga earlier this month, the "Born This Way" singer opened up about what she envisions for the future of her acting career.
"I think I'll always tell the stories of women because I am a woman and women have so many stories to share, and women are powerful, and women are vulnerable," she said. "And to be vulnerable and strong at the same time, I think is a special thing."