Helen Anker literally sparkles as Queen Guenevere in “Camelot” at Chanhassen Dinner Theatres, but offstage she’s no drama queen.

In fact, Anker, a lithe Brit whose plummy accent and short-cropped ’do make her seem like a cousin of Victoria “Posh Spice” Beckham, is so down-to-earth that she invited a reporter and photographer to her workout class — where the sparkle comes from sweat, not makeup.

No matter. On a recent weekday morning, Anker stretched, twisted and lunged for 45 minutes as she moved to throbbing music at the Resistance Movement studio in St. Paul. Like the others in the room, she was often tethered to bungee cords in a routine that combined Pilates, yoga and strength training. Unlike the others, she often smiled during the grimace-inducing moves.

Her thrice-weekly class is part of a regimen the 45-year-old actress uses to maintain her health and stamina for the long run of “Camelot.” Most acting gigs in the Twin Cities last three to six weeks, but Anker signed on for a five-month engagement that doesn’t end until Feb. 25. The grueling schedule includes eight performances a week, plus rehearsals as needed, with only Mondays off.

“The truth is, this [workout] also helps with my back,” said Anker, wiping away perspiration as she caught her breath after class. “The back pain is a legacy from my years as a ballet dancer, but more than anything, I love to work.”

The poise and magnetism that Anker displays as Guenevere are also present offstage. Although shy when not in character, she has a natural charisma that helped her get out of a speeding ticket last summer on the drive to the Twin Cities from her home in Los Angeles.

Her exercise teacher, Alexa Lautenbach, described her as so “lovely and open, she’s easy to fall in love with.”

At a nearby cafe afterward, the staff, charmed by her accent, took Anker’s order with broad smiles. Anker happily accepts the kudos she often receives away from the theater — performers live for plaudits, after all — but she tries to keep it in check. She was a child actor in England, and remembers the wages of a swollen head.

“I was a handful, to be frank,” she said. “I now know better.”

Starting young

In a way, Anker is fulfilling her parents’ dreams. Her father, a retired real estate agent, was a part-time magician often assisted by her mother, who was a radiographer.

“I used to be the one levitating and being cut in half, all that stuff,” said her mum, Susie Marment, during a holiday visit to the Twin Cities.

Born in Banbury, an English town northwest of London that is memorialized in a nursery rhyme (“Ride a cock horse to Banbury Cross to see a fine lady on a white horse”), Anker showed promise early on.

“She started going to ballet class at [age] 2 ½ and there was nothing you could do to stop her dancing,” her mother said. “We knew straightaway where she was headed, and, luckily, she had the talent to match her enthusiasm.”

Anker would go on to gain national recognition when, at 9, she was cast in the London West End revival of “The Sound of Music,” headlined by Petula Clark. Around that time, she also won the dance category for “Champion Child of the Year,” a nationally broadcast honor.

“It was a big deal to be presented with an award by Princess Margaret in front of the nation, but it was a little embarrassing because some of the other kids had done heroic things like saving people from fires,” she said.

At 11, Anker was accepted into the prestigious Royal Ballet School, boarding there until 16, when she decided that dancing wasn’t enough for her. For one thing, other girls had stronger claims to the prima ballerina slots.

“I didn’t want to be in the ballet corps,” she said. “I wanted to be in musical theater, to act and sing. I wanted to be a star.”

It proved to be a good choice. She performed in a slew of West End shows, including “Beautiful and Damned,” a seven-month run in which she played Zelda Fitzgerald from age 16 to 44; “Cats,” where she did three roles over a year and a half, and “Contact,” directed by Susan Stroman.

It was in that show that Anker recognized the perils of a long run. Her co-conspirator was Gavin Lee, a school chum who later starred as chimney sweep Bert in “Mary Poppins” on the West End and Broadway.

“We were in the background,” said Lee, “and to keep ourselves fresh and amused, we came up with games and scenarios for our characters — like we’ve had an argument or we’ve won the lottery. One time we decided that Helen would be blind and I would be deaf. Now imagine that with all these dance routines in the show.”

“It was terribly unprofessional of us but it kept the cast in hysterics,” said Anker.

These days, Anker is the star. When she’s onstage, the spotlight is on her. She can’t afford to play games.

“Guenevere is torn between these two men, and it’s a story about the heart,” said Anker. “But it’s a story about idealism. Arthur wants his court and kingdom to be run in an egalitarian, just way. And that’s a lovely message for us today.”

Our ‘Fair Lady’

Anker first made a splash in Minnesota in July 2014 in another Lerner and Loewe musical, “My Fair Lady.” She played ambitious flower girl Eliza Doolittle in a production that became one of the Guthrie Theater’s biggest hits.

That’s when “Camelot” director Michael Brindisi noticed her.

“I thought she was very engaging — a great actress with a lovely voice,” Brindisi said. “But the biggest surprise was how funny she made Eliza.”

Brindisi had been mulling a revival of “Camelot,” the 1960 musical about the idealistic King Arthur, who wants to rule by right instead of might, but whose queen becomes the focus of a love triangle with his chief knight, Lancelot.

Brindisi noticed qualities that other directors had picked up on.

“She finds the basic truth in every character she plays,” said director Rob Ashford, who cast her in “Peter Pan Live” for NBC-TV. “That rule applies to stage and screen, acting, singing and dancing.”

Ashford first tapped Anker for a London production of “Parade,” in which she played dual roles: a governor’s wife and a poor, uneducated mother grieving her murdered daughter. Anker “was equally brilliant in two roles that couldn’t be further away from each other,” said Ashford.

He also cast her in the Houston Grand Opera’s “Carousel.” Anker, he asserted, “is a true triple threat. Her acting and dancing and singing are all executed with equal brilliance,” he said. “That’s very rare and obviously sought after.”

Anker’s career has taken her from London to New York and now Los Angeles, where she’s been based for a couple of years.

“I want to give that world of TV a go,” she said.

Getting a lift

Back in the exercise class, Anker said she felt great. The endorphins had lifted her as she got ready to perform that evening.

“It’s not just physical exercise, but it helps to keep me engaged mentally,” she said.

Anker, who acted in “Promises Promises” on Broadway for seven months, prides herself on not missing performances because of illness. In addition to exercise, she takes care to eat right, stay hydrated and get enough rest. She eats chocolates and drinks coffee and spirits, in moderation.

“The thing is, if you enjoy what you’re doing, you’ll never tire of it,” she said. “And I love to act, to dance, to sing. I honestly think that just being happy helps you to be healthier.”

Guenevere is one of her favorite roles to date, if only because of the character’s journey from her late teens to her 30s, and the attendant emotional workout.

“When she starts the show, she’s so innocent with crazy ridiculous ideas, like she wants men to be killing themselves for her,” Anker said. “But then she grows, and she’s genuinely fallen in love with two people. What she dreamt does comes true. In the end, it’s sad that she loses everything.”

As she left the workout studio, cheery and full of verve, it was clear Anker had lost nothing but a little sweat.