Like its subject, Rupert Goolds biopic has its good nights and bad nights, but it’s always saved by a powerhouse Zellweger performance.

It’s safe to say that the life and death of Judy Garland is one of Hollywood’s great tragedies. Growing up one of Tinseltown’s most indelible figures, imprinting herself onto the American psyche in The Wizard of Oz and Meet Me in St. Louis, Garland’s life quickly devolved into an unpredictable spiral of erratic behavior, drug addiction, and eating disorders that would eventually take her life at the all-too-young age of 47. The candle that burns twice as bright burns half as long, said Shakespeare, and Judy certainly did that. Rupert Goold‘s Judy (a biopic loosely adapted by Tom Edge from Peter Quilter’s stage play End of the Rainbow) captures the last burning flickers of the flame in a meditative, if somewhat perfunctory, biopic.

Save for a few stylized flashbacks to Garland’s early life as a product of the studio system, Judy follows Garland (Renée Zellweger) during her five-week run in London performing at the Talk of the Town nightclub in 1968, six months before her death. At this point in her career, she’s exhausted all of her options, burned all her bridges: she subsists on $150 singing engagements with her two youngest children (Game of Thrones‘ Bella Ramsey and Lewin Lloyd) and can’t keep a hotel room to save her life. Left with no other choice, she jets off to London, leaving her kids in the care of their father, third husband Sid Luft (Rufus Sewell) while she scares up some money so they can be together again.

There, Judy finds a semblance of her old fame again, playing to a four-tier nightclub (“How many was Carnegie Hall?” “Five.”) at night and collapsing from pill-fueled exhaustion and boozy irascibility by day. Her moods swing as violently as the microphone cable she throws over her shoulder during her acts, and exuberant shows are followed just as often by crabby shouting matches at impatient patrons.

Of course, this is where we find the glitzy meat of Judy‘s presentation of Garland: Zellweger is as good as you’ve heard everyone say she is, disappearing into the creases and short, jagged hair of the aging star with remarkable alacrity. Every mood, mannerism and witticism of Garland is right there on Zellweger’s considered face; it’s a transformation of the highest order. (She certainly pulls off the ‘wears false teeth to play a famous music star’ act better than Rami Malek in Bohemian Rhapsody, to be sure.) On her bad nights, she’s shambolic, moody, stumbling from one bad situation to another and just as confused about how she got there as anyone else.

But on her good nights, she’s a triumph: Zellweger does her own singing (she did Chicago for God’s sake, of course she does), and she nails the chutes-and-ladders vibratto and halting cadence of Garland’s late-career performances. Goold shoots these sequences with a beautiful reverence for the star, the camera swooping to and fro while focusing intently on Zellweger’s pained, joyful face, letting the performer take the reins and command her audience. It’s a smart move to get out of Zellweger’s way and let her take the mic; after all, Judy is if nothing else a vehicle for the actress’ incredible talent.

It’s a smart move to get out of Zellweger’s way and let her take the mic.

Still, despite trapping itself in the kind of standard music-biopic notes and aesthetic choices you expect at this point, Judy manages to touch on the consumptive nature of celebrity and stardom. The aforementioned flashbacks focus on a young Judy (Darci Shaw, her ingenue sweetness prefacing the craggy lines of older Judy) squirming against studio-mandated diets and the predatory manipulation of Oz producer Louis B. Mayer (Richard Cordery). At times, these scenes seem to belabor the point: we can infer plenty from Zellweger’s pained performance of Judy, and the alternating trust and suspicion with which she greets people like new paramour Mickey (Finn Wittrock), who sees her as both lovely legend and business opportunity, or young assistant Rosalyn (a knowing, grounded Jessie Buckley) who occasionally acts as the mother figure she never had.

Sometimes, Goold stumbles a bit in trying to keep up with Zellweger’s twitchy, perfectly calibrated energy, and the rest of the film falls to the wayside. We don’t get to know anyone in Garland’s orbit well enough to really feel for them when she inevitably pushes them away, and a show-stopping rendition of “Somewhere Over the Rainbow” is undercut by a “clap if you believe in fairies” moment that’s mawkish to the point of cringeworthy.

But Zellweger — and Judy by extension — shows us exactly why Garland needed the spotlight, and needed her fans. Early in the film, Mayer stresses that the persona they’re constructing for her will be transformative for her audiences: “Your job is to give those people dreams.” In chiseling and shaping her into an abstraction, Judy isn’t allowed to eat, live, or behave like a normal person. But in that same way, she found joy and purpose in entertaining an audience. The public may chew her up and spit her out, use her up until she does in her 40s from the same barbiturates that made her a star. But as long as she gets to pour out her soul in front of a loving crowd, it’s all worth it.

Judy takes the spotlight in theaters September 27.

Judy Trailer: