West End stars come in all sizes, but they tend not to be pint-sized Argentinians possessed of legs that can kick above head height. Not that Elena Roger will get a chance to dance in the Donmar Warehouse production of Piaf, which brings London’s latest Eva Perón back centre-stage in a demanding part. Pam Gems’s 1978 play, instead, should give the 33-year-old Roger the opportunity to prove that her success in the recent revival of Evita was no fluke; the woman has what it takes to go the distance.

“Stand back, Buenos Aires!” Eva Perón sings in Evita, so it made sense that the heroine of the Andrew Lloyd Webber/Tim Rice musical should for the first time be played by someone from the very culture and country that the show is about. That explained the perhaps unexpected casting of Roger, a total unknown, in a role that had been touted for such Broadway divas as Wicked’s Idina Menzel or, closer to home, Denise van Outen.

Evita ran for a year at the Adelphi, after which Roger might have been expected to return home. Instead, she’s learning French and preparing herself for an even more gruelling task – one that requires its leading lady to suffer a dramatic decline eight times a week while putting over anew some of the 20th-century’s best-known and most bruising anthems to love, sweat and grief.

It’s not the easiest of follow-ups, agrees Roger, whose good cheer is at odds with the punishing life of the “Little Sparrow”. “Yeah, now I wonder, why did I choose Edith Piaf?” says Roger, as we meet during rehearsals. While playing Evita, she recalls, “people kept saying to me, ‘You can do Edith Piaf,’ maybe because Elaine Paige did it . . . Maybe it’s because I’m tiny and Elaine’s tiny.”

Evita got spectacular reviews and grew in power during the run. However, it was a commercial failure and did not transfer as hoped to Broadway. That left Roger in a city far away from home and not sure what her next move should be.

“I never wanted to leave Buenos Aires,” Roger notes in English that can be charmingly fractured. (She talks of being “very sensible” when she means “sensitive”.) “This was like a destiny thing, my coming to London for Evita. But of course I have had a career in my country for ten years doing musicals.” In January, she recorded a CD, Vientos del Sur, and in June took a tango show to Australia.

Piaf will allow Roger to go for broke as a performer. After all, if the story of the French chanteuse could win Jane Lapotaire a Tony Award and Marion Cotillard an Oscar, why shouldn’t Roger leave her mark, as well?

“Well, what can I do?” Roger wonders aloud on the choices available as an Argentinian making her way in an English language workplace. “I can’t be only a singer/dancer for ever, and I need to know how far away I can go from myself.”

She says she enjoys the dialogue. And whereas Lapotaire originated the part in London and New York by speaking Piaf’s guttural French in a cockney accent, Roger is retaining her own accent – with the aid of a vocal coach, “to make sure,” the actress laughs, crisply enunciating each word, “that I am clear.”

Roger had caught Cotillard’s much-praised screen turn in La Vie en Rose before this revival was ever mentioned. But now she says: “I tried watching the movie again but didn’t finish; I have to be careful what I’m playing because I have to create something comfortable for me to do.”

She continues: “I always think you can learn a lot from another performer, but your instrument is your own. It’s my instrument and I can do what my instrument can do; it has to be different. I won’t be able to play Piaf like Marion, ever.” Roger’s point of identification is different with Piaf than it was with Mrs Peron. “Yes, Eva Peron was an actress at the beginning but then she was a politician, and I don’t have anything to do with politics. Piaf I can understand because she was a performer, and I know the business.”

Eva Perón died in 1952 of cancer when she was the same age Roger is now. Piaf reached 47 before dying of cancer, which was long enough to lose a lover in a plane crash and to slip in and out of alcohol and drug-related rehab. Whereas Perón had a “rainbow tour”, Piaf, tellingly, is remembered for her “suicide tour”.

Surely, inhabiting such abbreviated if exalted lives must leave its mark on an actress? “I was scared but we’ll see; we have to go for the challenge,” says Roger.

Could Roger ever tackle a British role? “Maybe in six months but not now. I would have to learn to speak much better,” she says, speaking those last two words in a deliberately protracted, faux-posh accent. “At the beginning, when I came to do Evita, I thought, Why did they call me? But, well, we’ve seen that it was good for the production; now that I am here, I have to try all these roles that are there for foreign people, just to make the British people believe what I’m playing.”

One casualty of her work ethic has been Roger’s romance of two years with Javier López del Carrir, an Argentinian musician who returned home to Buenos Aires while Roger continued a West End spree that included a takeover stint in Boeing-Boeing, playing a randy Italian stewardess. “It was difficult for Javier because I was so busy and he was really wanting to be there getting on with his career.” How is she coping? “I’m fine; I really need that – to be alone – because I think I’m building something, and I need to try to stick to that; I have no time for a boyfriend.” Nor is she literally on her own: home for the moment is as a lodger in the North London flat of her Evita co-star, Matt Rawle, who is currently abseiling around the Garrick Theatre as Zorro.

Buenos Aires still exerts a pull. The youngest of three children, she talks lovingly of her family. Roger’s father bravely carried on despite a stroke six years ago, aged 67, that stopped him speaking – her parents came to London to see her in Evita.

The ties in her family seem as close as Piaf’s were fractured. “Piaf’s life went up and down, but I like to feel that she was quite a happy person, that whatever happened she never stopped singing.”

The life of Piaf

1915 Born – not, as legend has it, on the street – but in a Paris hospital. Abandoned by her mother
1929 Joins her father as a street performer
1935 Discovered by the nightclub owner Louis Leplée, who christens her the “Little Sparrow”
1936 Leplée murdered. Though Piaf is acquitted, suspicion casts a shadow on her burgeoning career
1940-45 Sung for German forces but also reputedly worked for the Resistance
1946 Records La Vie en Rose. An international career burgeons
1949 The love of her life, the boxer Marcel Cerdan, dies in a plane crash
1951 Badly injured in a car crash, exacerbating drink and morphine addictions
1952-56 Married to the singer Jacques Pills
1962 Weds Théo Sarapo, a Greek singer 20 years her junior
1963 Dies of cancer. About 100,000 fans attend the ceremony

Piaf is in preview and opens on Aug 13 at the Donmar Warehouse, London WC2 (www.donmarwarehouse.com 0870 0606624)

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