Elaine Paige in an ensemble production? That’s what it says on the tin. The Drowsy Chaperone is the show in question – a Canadian fringe offering turned Tony award-winning Broadway smash, now arriving on the West End with “the first lady of musical theatre” given top billing. “But I only have one song to sing,” Paige says, “and the rest of the time, I’m in the chorus.”

Although no one could question her zealous work ethic (she drove herself to breakdown performing in Pam Gems’s Piaf in 1993), Paige is not exactly known for her humility. In newspaper profiles, that dread word “difficult” is often applied, and yet here she is in the chorus line, cheerfully taking on a modest role in a musical with far more credibility and less bombast than the shows that made her name. The Drowsy Chaperone is a musical that celebrates and spoofs golden-age musicals – at one point, it makes a catty remark about Cats, one of the shows (along with Evita) which made her famous.

Paige doesn’t seem to mind – she’s too busy sending herself up as the waspish, pint-sized prima donna Beatrice Stockwell, forever trying to upstage the leggy leading lady. In a recent interview, Paige cited as “a common misperception of me” her supposed seriousness. The Drowsy Chaperone offers her a chance to earn her comedy spurs. “To hear people belly-laugh in the audience. That’s so rare. It’s wonderful to hear laughter like I’m hearing eight times a week,” she says.

So is Elaine Paige mellowing? Or were the spikier elements of her reputation always undeserved? It’s certainly true that, both onstage and at this interview, she doesn’t exactly radiate warmth – although, to be fair to her, our conversation takes place in stressed circumstances, 45 minutes before she takes to the stage. And in any case, who needs warmth, or lightness of touch, in the musicals of Andrew Lloyd Webber? Paige was the supreme interpreter of Lloyd Webber’s theatrical colossi. Her fans are Lloyd Webber’s, her critics are his, and her reputation is forever tainted, or gilded, by his own.

To Paige, the criticism is just snobbery. As far as she’s concerned, “I was very lucky, early on, to be part of the cutting edge of musical theatre. The time of Andrew Lloyd Webber and Tim Rice [was] the renaissance of British musical theatre. It was a wonderful time.”

The child of a milliner and an estate agent, Paige was born in Barnet, Hertfordshire, and showed early signs of a steely musical ambition. Though not academically gifted (she failed her 11-plus), she taught herself to read music at the piano and attended the Aida Foster Stage School, where, she has said, she began to feel she belonged.

Minor roles in Grease, Jesus Christ Superstarand Billy followed, but she felt stalled. At the age of 29 she seriously considered giving it all up to become a nursery nurse, but a meeting with Dustin Hoffman, who asked her to sing for him and made her promise not to give up, gave her the encouragement she needed.

Paige’s breakthrough came, at the age of 30, when she was cast in Evita – albeit as second choice to Julie Covington. (Five years earlier Paige was very nearly cast as Covington’s replacement in another iconic 1970s hit, The Rocky Horror Show. How different her life might have been . . .)

A career that at crucial moments seems blessed by serendipity progressed when in 1982 Judi Dench dropped out of Cats with an Achilles tendon injury. Paige duly inherited her most famous role, and the song, Memory, that would become her signature tune.

In more ways than one, this is the defining passage of Paige’s life. She wasn’t just Lloyd Webber and Rice’s star, but Rice’s lover too. By the time the relationship ended (Rice dithered too long over divorcing his wife), Paige had missed her moment to have children. She has never married, although last year she was to be found “giggling coquettishly” (in one interview) about her new, young, French lover. In this same era, meanwhile, with the help of No 1 singles such as I Know Him So Well (her duet with Barbara Dickson, taken from the musical Chess, remains the biggest-selling record yet by a female duo), Paige indelibly established herself as a musical theatre actress, a label against which, it seems, she has chafed ever since.

She has tried shape-shift-ng, with limited success. She once released an album “which marked a significant change in [musical] direction” – but it didn’t succeed, she complained, because “my audience find it too hard to absorb change . . . It was clearly too much for them.”

A decade ago she was threatening to quit musicals altogether (“I feel I’ve got nothing left to prove”), and in 1998 made her West End debut in a non-musical leading role in Peter Hall’s production of Molière’s The Misanthrope. Recently, she has popped up in a few telly dramas: Where the Heart Is, Agatha Christie’s A Murder is Announced. But “fundamentally, I am not asked to do things as a dramatic actress as often as I am [to do things] connected with music.”

For this, Paige blames Britain – and its scourge, snobbery. She’s the victim of us small-minded Brits twice over, first because we don’t give musical theatre enough respect, and secondly because “people don’t like you to move around too much,” she says. “You’re kept in your little niche.” These rules don’t apply in America, where no one will ever make a snide remark about her being “suburban” and where “you can do practically anything”.

Paige might have moved there permanently after her Broadway success as Norma Desmond in Sunset Boulevard but it wasn’t a good time. “My parents were elderly and I wanted to be here for them,” she says. “So it didn’t pan out.”

In his autobiography, Tim Rice talked about Paige’s “strange combination of sparky confidence and self-deprecating modesty”. But, at least in public, the need to assert her achievements far outweighs the self-deprecation, which is rare and seldom rings true. She talks about acting as if it were running a marathon. And she is straight on the defensive if any of my questions imply a criticism.

Do you have any regrets? “I don’t think so, no” she says, managing to make the very idea seem preposterous. “I can’t complain, can I?”

By Paige’s own admission, insecure actors are ten a penny, and she’s one of them. She tells me, as if it were a secret, “I’m not as confident as perhaps I seem.” But she doesn’t seem confident at all, and even her recent criticisms of How Do You Solve a Problem Like Maria?-style reality TV reveal her hypersensitivity to what others think. For a start, she resents the implication that acting is something that can be quickly learnt.

Furthermore, “if you’re a serious actor,” she says, “you wouldn’t put yourself up for one of those shows in case you got bumped off the first week and all your colleagues saw it.” (As a vocal critic of the phenomenon, Paige must be miffed to see Lloyd Webber referring to the Sound of Music starlet Connie Fisher as “my new Elaine Paige”.)

Her current insecurity relates to her age – she’s 60 next year. Maturity brings added confidence, she says – “but that’s about the only good thing that comes from it. I don’t relish the fact [of being 60] at all. It’s just that my body tells me I’m not 25 any more – which is really irritating.”

It’s a bit sad, this 59-year-old woman longing to be 25, but at least on this point, Paige is absolutely candid about her real feelings – and I find myself admiring her refusal to pay lip service to the usual “young-as-you-feel” pieties.

Likewise, I admire her in The Drowsy Chaperone. If she were half the diva she’s said to be, she wouldn’t be prepared to hoof away in the background, sublimating her stardom to a show whose star is the show itself. Perhaps her performance will dispel some of that snobbery she feels pursues her and that bedevils musical theatre too.

“What the show is saying is that musicals transport you to somewhere else,” she says. “You’re allowed to forget the ghastliness of real life for an hour and 40 minutes when you walk into a musical theatre house.”

Finally, on the issue that matters most to an entertainer – entertaining people – Paige rightly refuses to be insecure. “Music doesn’t have to be particularly cerebral, and what’s wrong with that? Life is tough enough. Let all that go, and allow musical theatre to be what it is, to just sort of wash over you. I’m of the view,” she says, “that that’s a good thing.”

The Drowsy Chaperone is previewing at the Novello Theatre, London WC2 (0870 0400046), and opens on Wednesday

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