Lady Gaga may be one of the world’s biggest musicians, but she can very well still be intimidated. In fact, she was so nervous on her first day of shooting “American Horror Story: Hotel” that she vomited in a plastic bag in her Rolls Royce on the way to the set — and handed the bag of puke to show co-creator Ryan Murphy.

“I threw up in the plastic bag and I saved it and brought it to Ryan Murphy,” Gaga told reporters at a press junket on the set of the FX horror anthology Wednesday. “He was like, ‘Oh, you think you can disgust me? You can’t.’ The thing is, you think you can’t get anything past him, but then he met me. And I’ll bring him a bag of my own vomit to the set.”

For Gaga, who plays bloodthirsty fashionista the Countess on the show, “AHS: Hotel” marks her biggest foray into acting yet. She joins a cast of bucket-list actors, including Kathy Bates and Angela Bassett, so she immersed herself into the role and “prepared [her] ass off” before stepping onto the set. “All I have is my preparation time and Jesus, really, to save me from possibly screwing this up,” she said.

When the news broke of Gaga’s involvement in the show and her character details, many believed that it was the perfect role for her. A high fashion diva who runs the hotel? It should be easy for the megastar.

But she said it was much more difficult than that, and she does not have quite as much in common with the ruthless Countess.

“I find it funny that people wonder if that’s just the way that I really am, so this was very easy for me to just kind of walk in here with my blonde hair on and just be a bitch and be rude to everyone and that’s just what I do, because you’ve seen me do something like that before,” she explained. “The truth is that it’s actually very challenging to be sincere when you have all of that on. It’s not comfortable. It’s never been comfortable for me.”

According to Gaga, Murphy told her to “be more of a bitch, be meaner, be more restrained” to bring out the Countess that the audience sees onscreen every Wednesday. To make the part look “effortless and honest,” Gaga studied killers like Anthony Perkins’ Norman Bates in “Psycho” and Anthony Hopkins’ Hannibal Lecter in “Silence of the Lambs,” as well as watching HBO miniseries “The Jinx,” which followed millionaire Robert Durst, who is at the heart of three murders.

But Gaga has found herself at home in the Countess. In fact, she does call it “dangerous” in terms of acting, as she’s started to think like her.

“If I’m out at a restaurant or I’m in the car and we’re driving past people, I sort of look at them and wonder, ‘Gee, I wonder if you’re clean. I wonder, if I were to kill you, if it would be worth it for me,'” she revealed.

And it has even followed her home, citing that her fiance Taylor Kinney even has to deal with the Countess: “It’s quite a challenge for Taylor as well at times because I just don’t give a f—k about s—t anymore. Because [the Countess] just can’t be, she’s been alive for 100 years. So no matter what goes on in her hotel, if she loses her cool, she can’t handle her s—t.”

The boldness comes out while the show is shooting, too. Gaga said during that much-hyped murderous foursome scene in the season premiere that she was confused that there wasn’t penetration. “I don’t get it. We’re going to kill them, and then f–k them and then makeout and then it’s over?,” she asked Murphy, who reeled her back in and told her, “It’s the first episode. We’ll get there.”

It makes sense that Gaga would go all-out for her first big role, though, because what she really wants in all of this is to be taken seriously.

“It’s always been so important to me that if I were to ever to make a move in television or as an actress that it would never feel like a move and nobody would ever go, ‘Oh, here she is trying to become an actress and put out a clothing line and a record label’ – you know, that’s sort of the thing that everyone expects, right? That it’s time for my empire,” she went on. “I don’t give a f—k about that. It is completely unfulfilling to me. It does nothing for my soul. What I did want was to be taken seriously as an actress.”

What Gaga also wants, though, isn’t too different from the Countess’ goal: to be celebrated and loved.

“I desperately so want for you all to love the real me and not the idea of me that you write about or see,” she said. “[The Countess] wants everyone in this hotel to love her for who she really is, cunning or not. Cunning, evil – she feels that they’re all here in this triumph of the hotel because of her. And she keeps them together and she wants to be rewarded for that, for who she really is, and not for anything else.”