Close-up: Kerry Ellis

Kerry Ellis has never starred in a soap opera or reality show. Yet somehow she's the leading lady in the West End's most successful musical. And next month, the 28-year-old will pack up her dancing shoes and green face-paint for Broadway, where she'll continue to play the role that's made her name this side of the pond: Elphaba, better known as the Wicked Witch of the West, in Wicked.

Ellis, who is set to release a Brian May-produced debut album before jetting off, began her career in less stellar circumstances, understudying Martine McCutcheon in My Fair Lady in 2000. When McCutcheon fell ill, Ellis got her break. And after appearing in Les Misérables and We Will Rock You, she became the first British Elphaba.

Wicked, which has made more than £45m since its London première in September 2006, reveals how Elphaba's ostracisation turned her into the bitter witch we know and hate in The Wizard of Oz. The theme resonated so well with youngsters that Schools Minister Ed Balls used the show as the launch pad for a £3m anti-bullying push.

"I get a lot of letters from kids who've been picked on," says Ellis. "By relating to Elphaba, they've understood why people can be perceived as different. It's such a powerful message."

Unlike so much of today's West End fare, Wicked is not a revival of a well-worn staple nor a cobbled-together collection of covers – which is just as Ellis likes it. "It's brilliant that this show is so successful with original music and an original story," she says. "It's not run by celebrities or TV shows. There's no gimmick." Like show, like star.

Wicked is at the Apollo , London SW1, www.wickedthemusical.co.uk