When Zoe Birkett was cast as Tina Turner in the hit West End musical of that extraordinary singer’s incredible life, she knew it would be hugely demanding. She alternates the physically challenging role with fellow musical theatre star Karis Anderson, performing five times one week, three times the next.

Never off the stage, Zoe must inhabit Tina by singing up a storm, dancing like a dervish and enduring brutal beatings from her controlling husband, Ike. To describe the part as tough is something of an understatement.

“What’s more,” she says, “I don’t think people quite understand the full extent of Tina’s traumatic life, which means digging deep into your emotions. It’s a three-hour roller coaster. It would be impossible to do two shows on the same day.”

Zoe, 39, first came to public attention when she was a runner-up to Will Young and Gareth Gates in 2001’s Pop Idol. Since 2009, she’s been playing leading roles in the West End: Priscilla Queen of the Desert, Thriller Live, The Bodyguard, Moulin Rouge, the Bake Off musical and The Witches at the National last year.

Whichever way you slice it, it’s an impressive roll call. What lifts it to another level, though, is that all this has been achieved against the backdrop of the severe and debilitating medical condition osteoarthritis.

You certainly wouldn’t know it sitting opposite her in her dressing room in London’s Aldwych Theatre. Trim and lively, there’s no hint of any physical handicap.

The first intimation that something was wrong occurred when she was 14 and, without warning, her left hip came out of its socket. To hold everything in place, she had three pins inserted into her leg.

“It was a terrible shock,” she tells me. “I’d been dancing since the age of three and now the surgeon was telling me I’d never dance again. After 18 months, the pins were removed and I learned to live with the pain, a perpetual dull ache that just became a part of my life.”

Only through sustained exercise was she able to pursue her first love, dancing. The problem accelerated, though, as the pandemic took hold. “I wasn’t doing as much exercise because we were all in lockdown,” she continues. “The result was that I started having trouble with my back. I couldn’t walk for more than five minutes.

“I couldn’t bend down. I couldn’t tie up my shoelaces. For years, I’d been sleeping with two pillows between my legs, the pain forcing me awake every couple of hours. And you can’t operate normally on a perpetual diet of broken sleep.”

A private scan revealed the extent of the damage. Still only in her mid-30s, Zoe needed a full hip replacement if she was to walk, never mind dance, comfortably again. “I was told that, if I left it any longer, I could kiss goodbye to my career because the discs in my back would have collapsed,” she reveals.

Even so, she wasn’t prepared for the diagnosis. “When I was told I had severe osteoarthritis, I couldn’t believe it.

“I was 35. Like most people, I guess, I’d always associated arthritis with the elderly. I asked about injections to ease the pain but I was told no: it was too far gone. I had to have a new hip.”

She pauses: “It’s no exaggeration to say that it felt like the end of my world: I thought my career was over.”

Courtesy of Covid, the NHS was swamped.

“In the end, I found an amazing surgeon, Professor Field, at the Lister Hospital in Chelsea. My main concern was the speed of my recovery. We were coming out of lockdown, I was part of the original cast of Moulin Rouge and the first night was only three months away. What I also needed to know was whether in the long-term I’d still have a career with my artificial hip.

“He explained I would if he used the anterior approach for the insertion of the titanium socket and stem. That means going in at the front of the hip as opposed to a posterior approach.”

The anterior option, he said, would give Zoe more flexibility – essential for a dancer – and her new left hip should last for up to 15 years. But, before the operation, she was urged to build up her muscle strength.

“My local gym was closed so my husband, Adam, emptied the garage and built a home gym. I then paid for a personal trainer to help me tone up my legs. I took up cycling on a static bike. I did spin classes and walked, but never ran, on the open road. I bought a special box for step-ups to strengthen my glutes. It was agony. But I’d try and do half an hour of exercise every day to get myself as fit as possible for the operation.

“I knew a long recovery period wasn’t an option. And I took up regular swimming which is really helpful if you have arthritis because it uses all of your body.”

In the event, Zoe was in and out of the Lister within the day. “When I woke up, the pain was different. I was sore from the incision in my leg, but that disappeared quite quickly.

“The wonderful thing was that the dull ache I’d experienced all my adult life was no more. For the first time ever, I could touch my toes. My husband no longer had to put on my socks for me. I started buying lace-up shoes. I also didn’t need an elevated disabled toilet any more; now I could sit on a regulation one.”

Two days later, Professor Field sent her a WhatsApp message. Was she exercising regularly? “I told him not yet,” she admits. “He wasn’t having that. If I was to get match fit, he said, I should walk two hours every day.”

And despite the loving support of her husband, who runs his own mortgage and insurance business, and their now seven-year-old daughter, Aaria, there was no one of her own age she could talk to.

It must have been hard to stay motivated in such circumstances? “Professor Field had told me that I’d suffer no more pain post-op. That alone was what kept me going.”

To this day, she exercises three times a week, although, as she points out, playing Tina is a workout in itself.

She’s also conscious of eating sensibly. “Lots of fruit, veg and protein which will help you maintain muscle strength, but no rice which can swell up in your body and aggravate joints. And I don’t touch alcohol.”

Zoe’s ordeal has prompted her to be there for others going through a similar experience and, most particularly, if they’re younger sufferers. “My inbox and social platforms are always open for people who want to seek advice and support.”

World Arthritis Day falls tomorrow. And it should be a big deal, given 10 million Britons are affected by some form of arthritis. “I know I’ll get an influx of calls and enquiries from fellow sufferers. I’m an ambassador for two charities, Versus Arthritis and Arthritis UK, and I’m happy to talk to anyone with the condition.”

Life is good for Zoe as she faces down her demons. But she never takes anything for granted. She adds with a wry smile: “Winter’s coming, the roads and pavements will get icy. I’m super-vigilant about not falling. I always wear shoes with soles that grip well. I’m taking my daughter to Lapland to meet Father Christmas for a couple of days, I’m going to be extra cautious then.”

The most difficult aspect of playing Tina, she says, are the fights with Ike, played by Rolan Bell.

“He throws me to the floor. Rolan never pushes me, he lets me fall backwards so I can control how I land.”

Nor has it been easy dancing in heels.

“In Bake Off and Moulin Rouge, I wore flat shoes. Now I’m in stilettos, made by a specialist who builds in ankle support. It’s fine.

“To be honest, I feel liberated. It’s like I’ve got my life back. This is the first time in my adult life that I’ve ever been pain-free. But none of this would be possible without the love and support of my husband and my mum, Tracey, who lives at the bottom of the garden and is Aaria’s full-time nanny.”

She can now say with confidence that she’s a better wife, mother and performer.

“I’m at the peak of my career and playing simply the best role ever. I like to think that Tina is looking down on me, smiling. She’s been an inspiration to me.”

* Visit tinathemusical.com or call the box office on 0845 200 7981