It’s February 2016. Backstage at Levi’s Stadium, Santa Clara, Chris Martin is doing vocal exercises with a Bristolian woman in her seventies. Minutes from now, Coldplay will headline the Super Bowl 50 halftime show before an audience of 115 million.

Martin, his nerves humming like a live wire, has flown out his vocal coach from London just for this. Not, one imagines, that he needed the training. After all, he’s Chris Martin! It’s just that, when she got wind of who else was on the bill – Beyoncé! Bruno Mars! – her eyebrows shot up. “Well,” Martin remembers her saying, “You’d better have a lesson, then.”

Her name is Mary Hammond. She has flaming red hair, and glacier-blue eyes that miss nothing. A doyenne of vocal coaching, loved within show business, unknown outside of it, she has taught everyone from Martin and Adele to Yungblud and Sir Ian McKellen.

“She’s never going to bulls*** you,” says Martin, who has enlisted her on each of the record five occasions that Coldplay have headlined Glastonbury. “A tiny drop of praise is worth barrelsful from anyone else. Her soul is warm. And because she’s a singer herself, she knows you need a kind of emotional protection. If she says you’ll be fine, you take that seriously – because she wouldn’t say it otherwise.”

For 26 years, Martin has been her student. Now I’m one, too. I spent much of my early thirties writing about other people’s voices for a living. My own, unvarnished, has been described – by a music critic buddy of mine – as having a “beautiful naivety” to it. Hmmm. She, at least, stayed to hear me throw the kitchen sink at Paul Simon’s “Graceland” during a celebrity party we once gate-crashed. I remember closing my eyes to emote the words “Losing love is like a window in your heart” and opening them to see that everyone within range had scattered. To be fair, it was Charlotte Church’s do, so they must have had higher expectations, but you get the idea. A mellifluous instrument it is not.

When the frontman of a band I know, placed with Hammond by his label, told me that anyone could learn to sing, I took it as a challenge. Surely no one could make my voice sound pleasant? I had to find out.

At Hammond’s house in north London, the windows are (mercifully) triple-glazed, an enormous Persian rug covers the floor, and a tuba sits in the corner with flowers arranged in its bell. Occupying the far wall is a harpsichord – black-lacquered, hand-painted, and built by her husband of more than 60 years, Peter, formerly a cellist with the London Philharmonic. A cello rests nearby; a double bass stands broodingly by the fireplace. Beside the grand piano, framed photographs crowd a bookshelf. One is of Hammond overseeing Martin as he practises. On my first visit, I pass Cruz Beckham on the doorstep on the way in (“a genuinely nice, down-to-earth young man”, observes Hammond).

Her ability to access an artist’s mindset, and pivot to how I’d approach a song, blew me away

Yungblud

In that lesson, she has me supine on the floor, my hand on my stomach, learning how air moves. “There’s no point in lying,” she tells me. “If something’s not working, I’ll tell you. And if something’s there, I’ll tell you that, too.” At the end, she asks me to sing. Anything I like. Convinced I possess a slinky falsetto, I choose “I Believe in a Thing Called Love” by neo-glam-rockers The Darkness. “That,” says Hammond afterwards, “reminded me of the time Dame Edna Everage stood at that very piano. Did you mean it to be comic?”

“Singing is such an exposing thing,” Yungblud tells me. The three-time Grammy winner, having briefly attended the Arts Educational School in west London, already had a certain theatricality; now his pliant vocals veer effortlessly from a growl to a howl. “Obviously, she’s unbelievable at exercises and strengthening the voice, but her ability to access an artist’s mindset, and pivot to how I’d approach a song, blew me away.”

No contemporary British vocal coach has accumulated quite the breadth of experience Hammond has. Trained at the Royal Academy in both singing and piano in the Sixties, she watched her contemporaries head for Glyndebourne and Stuttgart. Instead, she went to Southend pier to perform as a singer in a summer variety season; a baptism of fire, she says, but one that was in tune with her effervescent personality.

A stellar career as a session singer followed: from the BBC’s Friday Night Is Music Night to the great concert halls, from Sondheim to the Three Tenors, close enough to Pavarotti, Domingo and Caballé to hear them breathe. She sang on a Paul McCartney and Wings album – George Martin, she recalls, walked the microphone line checking who wasn’t blending, ensuring no single voice stood out. All the while she was raising the two children she’d had in her early twenties. In the late Eighties, she was a vocal coach on the first production of Les Misérables. Through the Nineties she set up the first postgraduate musical theatre course at the Royal Academy, becoming – show by show – the coach that West End producers called first.

“I just always had it,” says Hammond, of teaching. “It felt very natural.” In 2000, when Coldplay went stratospheric with the release of their debut album Parachutes, Martin phoned. He’d been told he’d never get her: “She’ll be too busy.” But Hammond made time – and it continues to matter. “I remember thinking it was a temporary thing, feeling intimidated,” Martin says of performing to large audiences. “But it isn’t.”

Mary has always been there at the important moments

Actor Janie Dee

In person, Hammond is magnificent company: funny, loquacious, and fond of a swear. When she laughs, her whole body moves, like a conductor bringing an orchestra to its feet. Over the course of a year, without either of us quite noticing, she becomes as much a confidante as a vocal coach. We go to the theatre together. She rings to check in. As my own anxiety bubbles up across those months, brought on by my parents’ failing health, I find myself trusting her in ways I hadn’t anticipated. Our conversations are a sort of analgesic balm for whatever is fraying.

“The thing about her being a mother figure, or even a grandmother – that’s part of her magic,” says Martin.

The consensus is that Hammond makes you feel safe. “Singing is vulnerable,” she explains. “Things on people’s minds – they just tumble out, I don’t ask.” Combining surgical precision with occasional afterburner blasts of warmth is what gives Hammond her particular, unshakeable authority. She’s indefatigable.

Janie Dee, a two-time Olivier winner whose turn in 2017 as showgirl Phyllis in Sondheim’s Follies at the National received rapturous applause, has known Hammond for nearly 50 years, having first been taught by her at the age of 14.

“She vibrated with energy,” Dee says of that first meeting. “She’s always been there at the important moments. I lost my voice once, just before an opening night. She dropped everything and came to the theatre. Afterwards, she told me to inhale steam to soothe my vocal cords and then rest, and that everything would be alright. She was right. But it was the fact that she came.”

By any measure, Hammond was ahead of her time. In an era when classical technique was the only accepted form of vocal training in Britain, she was among the first to explore new scientific research into the voice and to realise its relevance to teaching. While well versed in classical technique, she was also a proponent of ideas developed by American researcher Jo Estill, whose videos of the vocal tract explained, for the first time, the precise physical mechanics of “belt” (think Aretha Franklin), “twang” (Dolly Parton), and “tilt” (Sam Smith) – terms that are now established in voice-coaching vocabulary. “When you read about it in a book,” Hammond says, “I find it difficult to teach. I have to feel it.”

In practice, a lesson with Hammond is part science, part excavation. Breathing exercises come first – she equates air with the bow of a violin crossing a string. No air, no resonance. Then come the songs: Johnny Cash’s dolorous cover of “Hurt”, Frankie Valli’s life-affirming “Can’t Take My Eyes Off You”, Frank Sinatra’s swooning “Fly Me to the Moon” – each one requiring me to truly commit.

“When you’re scared of singing, you stop yourself,” Hammond says. Over the year, I learn to give it full throttle, for better or worse. Wincing slightly as I attempt one of my fortnightly arpeggios, she tells me repeatedly that there is a “texture” to my voice. “You’re not actually tone-deaf,” she adds.

Arty Froushan, who played Patrick Bateman in the Almeida’s recent production of American Psycho – a show I attend with Hammond – calls her “the guru to end all gurus” and credits her for the acclaim he received. “Her touch is so light that you don’t even realise you’re transforming,” he says. “And then, all of a sudden, one day, you can just do it.”

Yungblud’s experience has been rather more unconventional: she had him treat his entire 2025 album, Idols, like a Broadway score. “Very different for a rock musician,” he says. “The band call her Yoda.” His favourite moments, he adds, are “when she comes to rehearsals – she sits in the back like the Queen, her in-ears in, microphone in hand, shouting at me through the songs to drop my jaw”.

Beyond being a brilliant teacher, Hammond is a deep well of anecdotes. Name almost anyone in British show business and it’s likely she’s taught them. Last October, I mentioned I was interviewing actor Alan Cumming. “Oh, he’s been here,” she said. Ralph Fiennes (“Open-minded”), Dame Diana Rigg (“Meticulous”) and Graham Norton (“Hardworking”) have all been to see her, too.

She speaks about her students in the way a parent might – proudly and with a protectiveness that is unwavering. Of Martin, who she says boasts a palette that extends way beyond the plaintive falsetto for which he’s renowned, she is particularly effusive. “He’s warm, he’s kind. Not up his own arse at all.”

When Martin visited her in hospital, he brought his then wife Gwyneth Paltrow. And their children. The whole ward went quiet. Later, her surgeon appeared. “I hear you’ve had an important visitor,” he said. She shrugged. “Just somebody I teach.” Classic Hammond. “The bigger you get, the more truth you need to hear,” says Yungblud. “She doesn’t care who you are.”

Thanks to Hammond, my voice has improved. Not in any way that would trouble a recording studio, but enough that I recently, reluctantly sang in front of my mates at karaoke, and nobody dashed for the exit. More than the singing, though, I have made a wonderful friend. One, it turns out, whom I share with a lot of people. “She’s a true rock star,” says Yungblud. Another phrase crops up more than once. Both Dee and Martin put it like this: “I love her very much.”