Tracie Bennett as Judy Garland in "End of the Rainbow" Sara Krulwich/The New York Times Tracie Bennett as Judy Garland in "End of the Rainbow," (with Michael Cumpsty). The show opens Monday at the Belasco Theater on Broadway. JUDY GARLAND pops a great many pills in Act II of "End of the Rainbow," the new Broadway show about the consequences of her fame, set six months before her fatal overdose in 1969. Yet at a recent rehearsal Tracie Bennett, the actress portraying Garland, wasn't feeling sufficiently strung out as she sang "Come Rain or Come Shine" with her six-man orchestra in the show, which weaves famous Garland numbers with scenes set in her London hotel suite. "I'm off my face on drugs at this point," Ms. Bennett told the band, "so the faster you are, the bigger the crash-up might be for Judy. And I can tell from my breathing that I'm not struggling. When some of the musicians demurred, saying they were playing as feverishly as they could, Ms. Bennett, a veteran of British theater but an unknown in New York, recalled that a drummer developed blisters during a production of the work in the West End. "If the English can do it," she added, "you definitely can." By the second preview performance at the Belasco Theater on Broadway last month (the show opens Monday), the band was in overdrive during the song, and Ms. Bennett seemed on the verge of losing control as she punched through lyrics that reflected Garland's need to be loved, "I'm with you baby, I'm with you baby, I'm with you always!" Theatergoers that night, mostly men of a certain age, looked like they were holding their collective breath. Seconds later, when Ms. Bennett marked the crescendo by arching into one of Garland's signature poses, the house exhaled with applause. If "End of the Rainbow," written by Peter Quilter, is a tabloid portrait of Garland in twilight - Judy drinks! Judy swears! Judy falls! Judy throws an ashtray at her soon-to-be fifth husband, Mickey Deans! - Ms. Bennett is deeply protective of, almost reverent about, her character. It's not that she is a lifelong Garland admirer; growing up in northwest England in the 1960s, she preferred Gene Kelly movies. Rather, whether instructing her band or putting pressure on herself, Ms. Bennett said, she was preoccupied with illuminating and honoring "the essence of Garland" for those who might be suspicious of a Briton showing Broadway how Judy should be done. Garland, after all, has generations of fans and imitators, including many gay men who revere her as a fellow traveler in oppression. You can be sure that at least some of them will be taking to blogs and Twitter in the coming weeks to assess every twitch and fidget, every cadence and high note in Ms. Bennett's performance, her Broadway debut no less. "The expectations I've created in my mind are massive," said Ms. Bennett, a petite 50-year-old with a gunfire laugh - each burst lasts a good five seconds - and blond bangs when the Garland wig is off. But I've always tried to make the best of fear, then, because without fears there's no art. You need fear to create, to live. I am so scared of the sea, so what did I do? Learned to scuba in the Great Barrier Reef. And now I still physically shake in the wings before going onstage. The anxiety has endured, though Ms. Bennett has been playing versions of Garland on and off for more than a decade, including a more fictionalized one in a London pub production of this play - then known as "Last Song of the Nightingale" - and through last winter's critically acclaimed run of it in the West End. Mr. Quilter said he wanted Ms. Bennett because she was "fearless and willing to come close to breaking her neck." Ms. Bennett herself was blunter when guessing why she was chosen to play Garland instead of better-known actresses who might sell tickets on their names alone. "You need someone who is willing to be ugly inside and out, who will show no vanity through the spit and snot and tears, who will look like hell as Judy begins to decline," she said. "And here I am," she continued, her voice starting to quiver and her eyes turning swimmy with tears, "this former chorus girl who is finally being offered her big break. Being given a chance to make my mother proud. Make my family proud. So I can deal with the fear by working like hell to make them proud. And grueling work it is. Ms. Bennett's voice and stamina take a beating throughout "End of the Rainbow," and she is coping with eight performances a week by leaning into her pleasures - swigging Cosmopolitans, chain smoking - rather than retreating into the monastic life some singers lead when not onstage. She is single nowadays after a few serious romances. Ms. Bennett takes the usual steps to protect her voice (tea, honey, water, few if any conversations by telephone or in loud places) but she attributes her fortitude to the physical strength and work ethic that she came by growing up in the industrial north of Lancashire.