As Beyoncé rings in her 33rd year, it feels like there's one part of her career no one talks about anymore, including Beyoncé herself: being a serious actress. Her entire Hollywood career basically spans from 2001 (never forget Carmen: A Hip Hopera) to 2009 (forgettable campy potboiler Obsessed). Now, Decider had the guts to proclaim that she will "never" be a great actress – on her birthday, no less!

In the piece, Meghan O'Keefe argues that Beyoncé now seems wisely "content to just be Beyoncé." O'Keefe does at least acknowledge that Bey clearly worked to improve her acting before calling it quits.

It's true that Beyoncé's work in movies like Austin Powers in Goldmember or The Fighting Temptations felt perfunctory, and that she was outshone in Dreamgirls by her Oscar-winning co-star Jennifer Hudson. But it's a crying shame that she stopped acting not long after she delivered her best performance, in Darnell Martin's criminally under-seen Cadillac Records, where she played Etta James. A supporting performance that arrived with much hype, it largely missed out on awards attention when it bombed at the box office. Perhaps Beyoncé's work was crippled by high expectations, but that doesn't mean she wasn't doing something special.

Cadillac Records is, in general, one of the best music biopics of the last decade's tidal wave in that genre, focusing not just on one artist but the Chess Records label, which distributed the music of Muddy Waters, Chuck Berry, Howlin' Wolf and James among others. The entire ensemble (Jeffrey Wright, Mos Def, Eamonn Walker) is special, and the film is happily willing to explore the muddled ethics of Chess Records' owner Leonard (Adrien Brody) giving black musicians a wider audience while making huge profits at the same time.

And that is best exemplified by his relationship with "At Last" singer James (Knowles), the most tempestuous and fragile of Chess Records' success stories, who struggled with alcohol and drug addiction. It's such a showy, brassy role for Knowles, and so easily dismissible as a career stepping-stone for her — she was obviously making a very concerted effort to be a serious actress, and the challenge of playing James is similar to the challenge Diana Ross took on playing Billie Holliday in Lady Sings the Blues.

It's maybe not quite that revelatory a performance, but it's easily Knowles' best – and she doesn't just shine when she's singing. Credit to Martin's direction in general for knowing when to lean into the clichés of the musical biopic and let things get a little theatrical, but Knowles was just as powerful when she was being quiet. Unlike Dreamgirls (where she was mousy and a deliberate second fiddle outside of that one great number "Listen") or Obsessed (which was paint-by-numbers in every way), Martin harnessed Beyoncé's star power in the right way. You can't completely forget that she's Beyoncé, but she's playing someone who radiates a similar energy. The performance kicks into gear when James loses control, and what's when Cadillac Records is really something.

It's a crying shame in general that Cadillac Records never got a fair shake in theaters, for whatever reason. Like all the best music biopics, it knows that the music should largely speak for itself and leans back and lets those performances breathe (Walker's first scene recording in the studio as Muddy Waters captures all the terrifying power the real man must have exuded). And unlike Walk the Line and its ilk, it doesn't have to loop back around to one moment in its main character's life to try and give a sense that it's been anything other than a linear retelling of an interesting person's life. The scope of following a whole label, and the way it rose an fell on the rough seas of a changing industry, feels much more inherently cinematic. 

I don't know if Knowles will ever get back into the acting game – she has so many plates spinning at this point – but with Cadillac Records, it felt like she had finally figured out her greatest strengths on-screen. Even if it ends up no more than a curiosity in her overall career, it's something she can be proud of.