The closest Wicked comes to a Margaret Hamilton at the Gershwin is in the fiercely formidable Madame Morrible, a headmistress to wannabe witches and wizards. She’s played in regal italics by the incomparable Carole Shelley, who’s having a high old time of it.

“It’s such an audience-response piece I can’t help but be energized by playing her.”

A kind of committee has created Shelley’s commanding presence. “Susan Hilferty, who did my four costumes, and Tom Watson, who designed and made my three wigs, gave me 75 percent of my performance. You can’t just schlepp around in a bustle and a train. You have to walk — like a ramrod — and that suddenly gives you a strength, an energy, a dominance.”

But to give credit where credit is due, Carole came with all that — a by product, no doubt, of being a baby of the London blitz. This has served her well in life: She’s perpetually employed in theatre because of her willingness to follow in famous footsteps (Elaine Stritch in Show Boat, Linda Lavin in Broadway Bound, Dorothy Loudon in Noises Off).

And on those occasions, like Wicked, when she originates roles, she often gets Tony nods (Absurd Person Singular, Stepping Out), if not the award itself (her work in The Elephant Man and Constance Cummings’s in Wings resulted in Tony’s only Best-Actress-in-a-Play tie). Next year marks the 40th anniversary of her first alighting on these shores as half of the flighty Pigeon sisters (Gwendolyn to Monica Evans’s Cecily) pursued by The Odd Couple, ducking their clutches in three different mediums: Broadway (Art Carney and Walter Matthau), film (Jack Lemmon and Matthau) and TV (Tony Randall and Jack Klugman).

Those ditzy doxies have seen their day, she thinks: “I don’t think those sort of Pigeony girls — that naïveté, that sweetness, that innate cuteness — happen anymore. I think girls maybe do that when they’re 11. By 13, they’re little women — it’s a shame, but there it is.”

Last month, at the Nothing Like a Dame benefit, Carole officially came out of the closet as a cancer survivor. “I’m doing well. I’ve a year to go before the doctors say, ‘Go away.’” One of her favorite roles — Cabaret’s Fraulein Schneider — saw her through this crisis.

“I went back into the show a week after surgery. It was the only thing left that I could make a choice about. The only time I could stop thinking about my illness was to be at the theatre at six and put makeup on and go onstage. The toughest [song] was ‘What Would You Do?’ I had to work at not crying. ‘Time rushing by, what would you do? With the clock running down, what would you do?’ It was a place to put pain and not let go — until afterwards. There was a wonderful prop lady who’d catch me having a sob in the wings. The Cabaret people were so good to me. All the kids. Todd [Haimes, artistic director of the Roundabout Theatre Company]. All of them.”

Now, she’s well along The Road to Wellville (a movie of hers) — and it’s yellow-bricked!