Charlie Hunnam's new movie, Jungleland, sees him playing a rough-around-the-edges manager and coach to his younger brother (Jack O'Connell), a boxer looking for a break. When Collider's own Christina Radish spoke with Hunnam recently about the movie and his role in it, their discussion took a brief detour into Hunnam's past roles. In doing so, it reminded us of all the twists and turns his career has taken over the last 20 odd years that led him to this point, to Jungleland. Hunnam spoke to us about two of those big twists one being his brief run on the early '00s TV comedy Undeclared. The other was a game-changing decision to not take a role in Forgetting Sarah Marshall — a decision he's never spoken about until now.

But before we can share Hunnam's incredible Forgetting Sarah Marshall story (which he says he revealed publicly to us for the first time ever), the actor spoke to us about working with Judd Apatow on the short-lived Fox comedy Undeclared. The show, which ran for the 2001-2002 season, followed a group of college freshmen through the highs and lows of college life. Hunnam played Lloyd, a suave lothario and roommate of Steven (Jay Baruchel), the show's protagonist. Undeclared was Hunnam's second major TV role to that point — following his role on the original British Queer as Folk — and his biggest step into comedy at that point, too. (Who better to guide you as a comedic actor than Apatow, eh?) Given his work history with Apatow on Undeclared, would Hunnam ever want to re-team with him on another project?

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Image via Fox

"Yeah, it's funny, I surprised myself, both of the things that I wrote this year, I wrote for myself and one of them is straight satire and the other one has got a very strong comedy component. So, yeah, when I sat down and started to write, my heart let me know that is certainly something that I want to pursue more. I don't know specifically about that group. I would certainly work with Judd. I don't know if he'd be interested in working with me. He has not demonstrated that desire, over the last few years. So, I think that might answer the question for us."

When we joked that maybe Hunnam's role as Jax Teller on FX's Sons of Anarchy — his first major TV role post-Undeclared — was so off the beaten path of Apatow-esque entertainment that maybe it would scare the writer/director off, something seemed to click for Hunnam. To the joke, Hunnam answered with an intriguing story which eventually revealed why he had stepped away from the Apatow-produced 2008 comedy Forgetting Sarah Marshall— reasons which have largely been unclear to this day.

"Maybe. It's funny, I'll tell you a little story. Jason Segel wrote Forgetting Sarah Marshall for he and I to do together, and he wrote that [Russell Brand] role [of Aldous Snow] for me. I went and I did the table read and it was very successful. Judd was producing. I was in a dark night of the soul in my career, at that point, and felt as though I needed to seize the trajectory and that just wasn't really aligning with, at that period of my life and career, what I wanted to be doing. Jason was one of my best friends [the pair had worked together on 'Undeclared'], which is why he wrote the film for me, but I had to tell him, 'I'm so sorry, I'm not gonna do this.' It was one of those things where that wasn't very well received by the inner circle of that production. I had to stand my ground and say, 'Listen, it's nothing personal. I'm just following my North star. I'm just in a weird spot and I'm trying to define for myself what the path forward is.'"

After declining to tackle the Aldous Snow role, Hunnam realized he'd made the right decision. Not just because of the personal and professional reasons he shared with us, but because it was obvious to him that Russell Brand was the best choice. Hunnam went on to tell us about the moment of clarity he had about Brand playing Aldous in the months after stepping away from Forgetting Sarah Marshall.

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Image via Universal Pictures

"It was one of those things where it was really difficult for me for the few months after that or a year after that, and then I saw this piece of stand-up. I didn't know who Russell Brand was, but I saw this piece of stand-up that Russell Brand did on Christmas day with my mom. It was just this liberating moment where I said, 'Obviously, that's the dude who should have been playing that role. Clearly, I just needed to step out of the way of the universe manifesting itself, the way that it was supposed to.' My relationship with Jason gave birth to that character, but there's no way I could have done it justice the way Russell Brand did. I think there's a rhythm to these things and you just have to really follow your instincts. It's all you can really ever do. I suppose I brought that up because it's a nice example of my instincts being proven to me that it was correct, I think. By the way, I've never told anyone that story before. I don't know if that makes it attractive or not — but it's a world exclusive."

While we may never know what Hunnam would have brought to the role of Aldous Snow, we have numerous other killer performances from the Brit made at the same time as, and after, Forgetting Sarah Marshall. Hunnam took a huge leap in his career with the role of Jax Teller, playing the leader of a California biker gang from 2008 to 2014. Following his time on the gritty crime drama, Hunnam appeared in hits like Pacific RimCrimson Peak, and King Arthur: The Legend of the Sword. And you know what? That's a pretty stellar trade-off if you ask me.

Jungleland is out on premium VOD beginning Tuesday, November 10.

Allie Gemmill is the Weekend Contributing Editor for Collider. You can follow them on Twitter @_matineeidle.