Perhaps she can capture the full emotional impact of Ms. Garland’s last chapter the way that the great female impersonators, such as Jim Bailey and Tommy Femia, did fleetingly but brilliantly through songs and a bit of nightclub banter in their careers.

Part of the Judy allure is, of course, her tragic demise: It’s the classic life-cut-short tale so many of us are drawn to, from James Dean to Janis Joplin to Prince. Her unparalleled celebrity also remains intriguing; as with figures such as Michael Jackson and Marilyn Monroe, Judy Garland’s highs and lows — the booze, the pills, the husbands, the meltdowns on the Hollywood set — loom large.

But it’s her raw talent that has kept her in that never-fade-out posthumous spotlight that shines on so few. There’s a good chance we won’t have Ariana Grande impersonators in sophisticated nightclubs in 30 years or YouTube deconstructions for those who think Lady Gaga was robbed of an Oscar for her performance in “A Star Is Born” 65 years from now the way we’re still analyzing Ms. Garland’s loss in the same role to Grace Kelly in 1955. (Groucho Marx reportedly sent Ms. Garland a telegram the next day: “Dear Judy, this is the biggest robbery since Brinks.”)

The internet has also kept the Judy mystique alive in both hilarious and reverent ways. Just witness the Punchy Players online with their splicing of clips of Ms. Garland and her daughter Liza Minnelli from Ms. Garland’s 1960s TV show into a skit about grocery shopping (complete with Ann Miller at the checkout counter). Or the various takes of “The Man That Got Away” from “A Star Is Born,” especially the final cut, which may be the greatest 4 minutes and 38 seconds you’ll spend on this planet. Or consider a 14-minute YouTube retrospective of her career. It’s exhausting to watch what a person can pack into 47 years.

The saddest part of “Judy” hitting big screens soon is that we know how it will end. We know that Ms. Garland did not fade into old age. She didn’t wave to her fans from a balcony as Doris Day did in her 90s. Nor did she become a staple of ’70s variety shows like Bob Hope or a fixture on daily talk shows like Zsa Zsa Gabor. Ms. Garland truly burned out — a victim of the Golden Age of Hollywood that served up so many victims as it churned out the facade of happiness and hope for generations.

But little Frances Gumm of Grand Rapids, Minn., was transformed into Judy Garland — in all her brilliance and tragedy — and the joy she brought to millions is singular, if only through the lens of “The Wizard of Oz,” perhaps the most watched and rewatched movie of all time, 80 years later. “Judy” will depict Ms. Garland’s last chapter in all its sad finality, but we’ll have Judy again for a couple of hours. And then we can go home and rely on YouTube and our memories to help get us through, come rain or come shine.

David Belcher is an editor and writer with the Opinion section in Hong Kong.