While fans have had mixed feelings about the Captain America musical on Hawkeye, one question many have shared is how the writers inside the universe knew about Steve Rogers' catchphrase.

Composer and co-lyricist Marc Shaiman spoke to Inverse about creating Rogers: The Musical and the song "Save the City," which appears in the first episode of Hawkeye and is seen in full during the finale's mid-credits scene. But before the outlet dove into his process, it asked Shaiman how the in-universe lyricists would've known Captain America frequently says "I can do this all day," a version of which is prominently featured in the song.

RELATED: Why Hawkeye Included Ant-Man in Rogers: The Musical

"We talked about that with [Hawkeye showrunner] Rhys Thomas," Shaiman revealed. "We just figured in the universe, people writing a musical or writing a book or writing a magazine article would've done their due diligence and homework and interviewed people who had been there. Perhaps, even in things that we've never seen, members of the Avengers had actually given interviews about this or that."

While audiences have only heard Steve say the line in intimate moments with other characters, it's clear that he's uttered it many times before seeing how casually the past version of Captain America throws it out in Avengers: Endgame. As such, it's not hard to imagine the phrase has gotten around, especially if someone like Tony Stark or Natasha Romanoff were ribbing Steven in the press.

RELATED: Hawkeye Director Wanted Ant-Man to Cameo

"There was a certain amount of liberty about that," Shaiman continued. "Maybe Natasha in some interview on CNN might have said, 'Oh, you know this guy, he's always like, "I could do this all day."' It could have come up somehow. The same thing applies to including lyrics about getting some shawarma when we're done. I wrote these things and no one objected to them! But we did talk about that. And we just figured that they don't say these things in a total vacuum. And you know how Marvel people are, you would’ve thought they would say 'No, no, this isn’t possible.' But from Kevin Feige on down, they were like 'This is good.'"

For fans, the lyrics of the musical are a wink at many of the iconic moments in Steve's life. But of course, digging too deeply into the logistics might clash with the in-universe possibilities. Hawkeye makes clear, however, that the average citizen knows quite a bit about the lives and deeds of superheroes. Inside the MCU, they're gigantic celebrities, so naturally, even the most personal details about the Avengers would be public knowledge by the time the show takes place.

Season 1 of Hawkeye is now streaming on Disney+.

KEEP READING: Spider-Man: No Way Home’s Opening Scene Already Connects to Hawkeye

Source: Inverse