Between racking up a bunch of producer credits, filming two Fast & Furiousmovies, and knocking out more Dior commercials than you can shake a perfume bottle at, Charlize Theron has had a busy decade.

And with her new (freshly Oscar-nominated) movie Bombshellcoming out this week, the twenties are looking set to be every bit as action-packed for the actor.

But hang on just a moment. It would be frankly irresponsible of us to breeze into a new decade of Theron-themed brilliance without pausing to reflect on one of her all-time best (and wildly underrated) movies: the 2011 comedy/drama Young Adult.

If you've never seen or even heard of this movie, you're not alone. Despite being made by the hot-off-their-Juno-success power team of Jason Reitman and Diablo Cody — and despite being positively reviewed — it didn't do all that well audience-wise: The film grossed a little under $23m worldwide, which is less than 10% of what Junomade. Its Rotten Tomatoes audience score is a disappointing 49%. For whatever reason, the film just didn't click with people.

I can't get enough of it, though. There aren't many movies I'll readily watch over and over again, or that I babblingly recommend to as many people as possible — but Young Adultcompletely fits the bill.

The movie follows an alcoholic ghost writer and former prom queen, Mavis Gary, as she returns to her hometown with the sole purpose of rekindling a romance with her high school boyfriend (who is now very much married with a kid).

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The trailer above doesn't really do the film justice, in my opinion. It sets the movie up as a fairly straight comedy, but it's actually way darker than that — a tragic study of what happens when characters can't extricate themselves from the people they were in high school.

Theron's performance is, without exaggeration, one of my all-time favorite pieces of acting. Gary as a character is bitter, insecure, and completely compelling. At times you pity her, at times you hate her. Theron takes Cody's brilliant writing and brings it to life in a way that's often painful to watch.

Theron has the perfect acting partner, too. Patton Oswalt stars in the movie as Matt Freehauf — a former high school peer whom Gary bumps into when she's back in her old hometown, and whom she barely even remembers. Freehauf was at the opposite end of the food chain to Gary — a boy who made the news when he was attacked by other students, leaving him with a permanent limp and a legacy of old headlines that are the only thing Gary can recall about him.

Patton Oswalt is also excellent in 'Young Adult.'Credit: paramount

In their own, very different ways, they're both just as trapped in the past as each other, and the almost-friendship they strike up leads to some exchanges that I still think about, almost a decade after I first saw the film.

"He knew me when I was at my best," Gary tells Freehauf at one point in the movie, after he asks her why she's so obsessed with her old boyfriend.

"You weren't your best then, Mavis," he responds. "I saw you every day. You had this little mirror in your locker. It was shaped like a heart, and you looked at that mirror more than you ever looked at me. And I was at my best."

Young Adult is available to stream on Netflix and Amazon Prime.