A succinct instruction to a professional hitman? No, the request for “two deadly murders” that I overheard at the Mill at Sonning box office was simply a request for two tickets for the forthcoming thriller Deadly Murder.

But before those macabre proceedings are unveiled, the Mill is staging something entirely different: the world premiere of the musical A Sentimental Journey — The Story of Doris Day.

Moving from box office counter to rehearsal studio, I discovered that Doris’s wholesome smile, perfect row of gleaming teeth, and beguiling voice were already working at full wattage to warm up a cold, dreary winter’s morning.

Except, of course, that the real Doris Day lives in California, is about to celebrate her 85th birthday (she was born on April 3, 1924), and devotes herself to charitable work with animals.

At Sonning, she is played by the Mill’s artistic director, Sally Hughes, who even early in the rehearsal schedule had already acquired the trademark Doris smiling lips and eyes, and the careful switching on and off of vibrato as she delivered the jaunty songs.

With almost 40 films, and more than 650 recordings to chose from, I wondered how Sally had gone about her research.

“I’ve watched all the films, and listened to the way she sings. I don’t usually have a vibrato in my voice, so I’ve had to build that in. Then you’ve got to go with what the script tells you — the films don’t tell you about her private life, which is also covered in this show.

“She was married four times, and lost her son only five years ago. But reading about her, she is a very upbeat person — she always saw the bright side of things. I think the accent’s very important, too — the Mid-Western accent. It determines how she sings.”

Sally is blond, so there’s no need for a wig or gallons of hair dye. But, she told me: “I’ve got green eyes, not blue like Doris. So I am going to wear blue contact lenses. People say the audience won’t notice if my eyes are the wrong colour, but I’ll feel better about it.”

Meanwhile, choreographer Joe Pitcher was painstakingly rehearsing the associated dance routines. “That was right, absolutely right,” he said encouragingly — one of the actors involved was finding it difficult to turn himself into a hoofer.

As one who was once snapped at by a complete stranger at a barn dance — “It would be very helpful if you knew your right foot from your left” — he had my deepest sympathy.

Musical director Jo Stewart was adept at gradually increasing the tempo as the steps fell into place.

“Knees,” came a purring voice from just beside me. “You’re doing very well guys, but the knees aren’t co-ordinated.” Award-winning veteran director Alvin Rakoff had hitherto looked on with an avuncular smile, but now he gently infused himself into the proceedings.

Rakoff is perhaps best known locally for directing Laurence Olivier as the late John Mortimer’s father in A Voyage Round my Father. He’s also directed Sean Connery, Rex Harrison, Michael Caine, Celia Johnson, Jean Simmons and Ava Gardner, among many other stars. But never Doris Day herself. Would he like to have done so?

“No, I wouldn’t. A friend of mine, Norman Jewison — we were both aspiring directors in Toronto, Canada — he went on to direct Doris Day. Directors are notoriously jealous of what other directors do, but I wasn’t jealous of him on this occasion.

“I was a kitchen sink man. Doris Day, with all her glitz, was not my sort of lady. It wasn’t that she was difficult to deal with — from what I’ve heard of her she was a very affable woman, good, and co-operative. Not that it would have put me off — I’ve dealt with many difficult people in my time.”

What, then, drew Alvin Rakoff to direct a new musical about Doris Day?Rakoff paused, before answering with a chuckle.

“The fact that it’s a young writer, Adam Rolston, only 25-years-old, who came up with this idea. And when I saw the script, I realised that her life wasn’t all that it appeared to be — it wasn’t all glamorous. She had been around the block, like most of us, and, to mix metaphors, had received a kick in the pants several times.

“She was a band girl at 15 — that means travelling from gig to gig with buses full of men called musicians, almost all of them young. You can imagine what happened then.

“She was married at 17, and a mother a year later — there’s this thing of her being the well-scrubbed virgin of all time, but she was a mother at 18. It’s quite surprising. And that was with husband number one, whose great delight in life was to beat her, until he blew his brains out one day.

“But by that time she had moved on to husband number two, who was supposedly rational, and sane. Except that he was insanely jealous of her, and so he left her. He couldn’t take her fame, and his non-fame.

“Husband number three was a Hollywood agent, who robbed her of every penny she earned. As for her fourth husband, as Doris says in the script: ‘If men were apples, I’d go to the barrel and pick the rotten ones’.”

It’s all the more amazing, then, that Doris Day projected this relentlessly sunny personality.“That is the most amazing thing about her,” Alvin agreed. “She does convey this wonderful, happy personality, that people identify with. It’s the blond cheerleader look, and people love it.”

lA Sentimental Journey – The Story of Doris Day runs at the Mill at Sonning until April 19. Box office: 0118 969 8000. Website: www.millatsonning.com. See review Page 5.