We've seen this time and time again, just cause a film doesn't score at the box office, doesn't mean that it isn't a success in its own way.

Looking back, 'Kiss Kiss Bang Bang' didn't shatter records at the box office, and in fact, it bombed and under-performed, bringing a near $15 million, which was the budget for the film.

However, take a closer look at the movie itself and it becomes evident, the mystery and crime film is very underrated and the critics agreed, as it received good reviews.

More importantly, it launched the career of Michelle Monaghan, who was quite green at the time. As for Robert Downey Jr., it arguably changed his career as well. Suddenly, the likes of Jon Favreau viewed Downey Jr. in a different light, and it would unlock an entirely different path in his career.

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For what it's worth, Downey had a blast with the role alongside Val Kilmer, calling it one of the best of his career.

A lot of good came from it, though in addition, things were very stressful for some of the stars. Michelle Monaghan recalls her massive anxiety prior to a certain scene. We'll delve into that story, along with the impact the film had on the cast.

Downey Jr. Called The Film His Best Work

With all the classics he worked on in the past, Downey Jr. calls this film his best work. Surprisingly, he heard about the movie randomly, and it was initially going to be offered to Johnny Knoxville. 

"The then-not-yet-Mrs. Downey [producer Susan Levin] was reading the script in our collective bedchamber, laughing her ass off. I say, “What is so damn funny?” She says, “Oh, it’s just this thing we’re going to offer Johnny Knoxville, a really funny Shane Black script.” Later Joel Silver said, “The good news about you is that you’re still cheap.”

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Downey Jr. ultimately got his hands on the script and he ran with it.

Despite the limited success, Downey calls the role some of his best work and in addition, his peers started looking at his potential differently.

"Kiss Kiss Bang Bang, which is, I think, in some ways the best film I've ever done. It wound up being a calling card."

"It came out, and it bombed, but Jon Favreau saw it, and he said, 'This guy could do an action movie.' And so that wound up being my calling card into the Marvel Universe."

A huge moment for Downey, though he wasn't the only one to profit from the experience.

Monaghan's Career Changed After The Film

Unlike Downey Jr. and Val Kilmer, Monaghan wasn't as established in the Hollywood realm just yet.

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Appearing alongside such stars, it not only changed her career but the way she looked at acting as well.

"It was a mind-blowing experience, and I think it was so integral to my success at the beginning of my career, for sure. That role really did put me on the map for sure, and it also taught me a lot."

"I hadn't studied acting, so turning up to set every single day, working with the likes of Robert and Val, was just invaluable. I learned how to find my mark on that movie. Like, every single day basically it was, 'Michelle, your mark, your mark, your mark,' and Robert taught me how to do improv on that film ... He's just got the most incredible timing, and it would take flexibility."

Speaking with Looper, Michelle admits the experience is still a special one in her heart despite all the success that would follow. It was a chance few get to enjoy, "I realize how unique of an opportunity that really was, and how fortunate I was to have had it, and had such a positive experience."

It wasn't all fun and smiles, in fact, Monaghan recently admitted that things got very stressful on-set, especially prior to a certain scene.

Terrifying Improv

Imagine the scenario of being new to the business and then just prior to a scene, a legendary actor tells you, forget about the words and let's just play off each other...

That was exactly the case between Michelle and Robert prior to a scene. They hit the stage just completely playing off one another.

Monaghan recalls panicking just prior to the scene. Ultimately, despite all the stress, the two were able to pull off the scene naturally and with the utmost ease.

It was yet another example of how special Robert Downey Jr. is, especially when it comes to his improv skills.

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Sources: YouTube, Looper, Cinema Blend & Rolling Stone