Bradley Cooper has proven himself to be a major Hollywood hero.

One of the first times he met Carey Mulligan, the actress who would go on to co-star with him in "Maestro," she was injured so badly that he took her to the emergency room, the two actors revealed in a new interview.

"Carey was in a one-woman show, and I went backstage to meet her and realized something was not right, and I insisted on taking her to the emergency room," Cooper recounted as he and Mulligan appeared on "The Graham Norton Show," per People.

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Mulligan jumped in to explain that a piece of the set had hit her on the head, saying, "I carried on, but when it was over, I started crying and thought I was a goner."

She added, "I was sobbing on the floor when Bradley turned up and, realizing I wasn’t okay, he took me to hospital. You can imagine how delighted the nurse was!"

Cooper and Mulligan have been nominated for Academy Awards for Best Actor in a Leading Role and Best Actress in a Leading Role for their work in "Maestro." Cooper, who also directed and co-wrote the film, plays composer Leonard Bernstein while Mulligan plays his wife, Felicia Montealegre.

The film takes place across the span of several years, and they both wore heavy prosthetics at different points in filming. Mulligan mentioned during the interview with Norton that at one point during the making of the movie, she had been "quite ill" and a doctor had been called in for her.

"When I told him I was 12 weeks pregnant, he was not at all convinced," she said, then he realized she was "still made up to look 57 years old."

"I couldn’t wait to tell the make-up artists how good they were," she noted.

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While Cooper is being lauded for coming to Mulligan's rescue, caring for celebrities is becoming a habit for him.

In November, Brooke Shields revealed to Glamour that he had come to her aid after she had suffered a grand mal seizure.

The supermodel recalled being in New York City for her own one-woman show, "Previously Owned by Brooke Shields," when she began to feel off. She had blacked out and gone "headfirst into the wall," while "frothing at the mouth, totally blue, trying to swallow my tongue. The next thing I remember, I’m being loaded into an ambulance. I have oxygen on."

When she awoke in the ambulance, she realized, "Bradley f---ing Cooper is sitting next to me holding my hand."

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The "Blue Lagoon" star admitted the experience was "surreal" and could barely wrap her head around the actor’s presence.

"I didn’t have a sense of humor. I couldn’t really get any words out," she told Glamour. "But I thought to myself, This is what death must be like. You wake up and Bradley Cooper’s going, ‘I’m going to go to the hospital with you, Brooke,’ and he’s holding my hand. And I’m looking at my hand, I’m looking at Bradley Cooper’s hand in my hand, and I’m like, ‘This is odd and surreal.’"

Fox News Digital's Elizabeth Stanton contributed to this report.