Renee Zellweger dug deep and transformed herself into Judy Garland.

From dieting into emaciation—the bones in her chest and back are visible—to assuming the marionette-like posture to capturing the vulnerability and insecurity of the showbiz legend, Zellweger is unrecognizable as she delivers an Oscar-worthy performance.

The film follows Garland as she arrives in London to perform a series of sold-out concerts at The Talk of the Town. Throughout the five weeks, she struggles with stage fright, alcohol, and drug abuse; tests the patience of her assistant Rosalyn Wilder (Jessie Buckley); and battles with her needling ex-husband played by Rufus Sewell.

In spite of these challenges, Garland still manages to charm her fellow musicians and fans. One of the more poignant scenes involves a brief interlude with an older gay couple who are long-time fans. Amid all this drama, she embarks on a whirlwind romance with Mickey Deans (Finn Wittrock), her soon-to-be fifth husband.

Barely able to function and unable to sleep, Garland is haunted by ghosts from the past. Flashbacks to the set of “The Wizard of Oz,” reveal the shocking and abusive behavior of Louis B. Mayer (Richard Cordery) and the MGM studio staff. Determined to keep a tight rein on the teenage Garland (Darci Shaw), the powers-at-be manipulate her into taking amphetamines so she could stay slim and work 16-hour days.

At age 47, Garland is far from her prime but still able to delight her audiences with several show-stopping performances. Unfortunately, bad behavior surfaces at several points in the film. One of the most heart-wrenching scenes occurs near the end of the five-week run. Garland pleads with the audience, “You won’t forget me, will you? Promise me you won’t.”

A must-see film that will linger in consciousness.