SHEENA Easton has coaxed a range of emotions out of Scotland's collective consciousness since she made it on to television in 1979 with the BBC’s let’s-make-a-pop-star documentary The Big Time.

We were delighted for the girl from Bellshill when she quickly came out with two pop hits, Modern Girl and Nine to Five, both catchier than a verruca at the baths.

We were stunned when she rocketed to international fame with a James Bond theme song, because although a terrific singer (listen to her performance of Hoagy Carmichael’s The Nearness of You) she’s not Barbra Streisand, the singer whose career little Sheena Shirley Orr hoped to emulate.

And of course we took the huff when she came back to perform at Glasgow Green in 1990, bringing with her a Debbie Reynolds accent. But what does the lady herself make of the journey? And how did she go from being a student at Glasgow’s RSAMD one minute, performing gigs at night for dental conventions and the like, and the next her smile could be seen all over Sunset Boulevard billboards?

We meet in a quiet corner of the Theatre Royal, Drury Lane in the heart of London’s West End where Easton is set to star in musical theatre classic, 42nd Street. The singer, who will turn 58 next month, is wearing a black trouser ensemble and her hair hints at aubergine. She looks great and if she has had any work done by her fourth (“and last”) husband, a plastic surgeon, I can't spot it.

Easton seems a little wary but that’s understandable. She’s been burned more times than the lead actress in a touring production of Saint Joan. So let’s start easy. How does she feel about making her West End debut as Dorothy Brock, the Broadway diva? “Well, I have done Broadway twice, including Man of La Mancha.” And Grease, Sheena. “Yes, but that was less serious,” she says in corrective tone, suggesting the teaching element in her RSAMD degree course wasn’t wasted. “This show is hardcore, but it’s not that I haven’t been performing. If I’m not appearing with my band I’m out doing symphonies, a couple of times a month at least.”

But there is more to learn in a musical theatre show. “Yes, but I came in knowing the book and all the songs,” she says. “It’s preparation. It’s part of my ethic when I take on a job.”

Easton expands on her character, the diva who can’t bear to see the younger singer shine. “Dorothy would be the type to sweep into a restaurant and make a statement. And that’s fun for me to play because I’m not a sweeper in real life. I tend to squeeze in, sit in the corner, have my lunch and leave.”

Did Easton’s North Lanarkshire upbringing, as one of six children, rule out future divaness? “There was certainly no get-out-of-jail-free card in life handed out,” she explains. “My father dying when I was 10, and being ill for a couple of years before that, prepared me for anything. Then my mum had to leave home at 5am to work in a factory. I learned how to set the alarm clock, get myself up for school, do my homework when I got home, have the potatoes peeled. And tidy the house.

“There was no concept of choice. Things had to be done. And that’s how I approached the rest of my life.”

What had to be done was to become a successful singer. First she signed up for a teaching/performance degree at the RSAMD, now the Royal Conservatoire of Scotland. “That was pragmatism,” she explains. “I was taught the same performance skills as the actors. I felt if I couldn’t make a living as a singer I’d teach during the day and sing at night. I didn’t want to head to London and wait tables and hope.”

She didn’t have to. The BBC came calling. Easton became a talking point but not all the talk was positive. Lulu’s manager Marion Massey said the young Sheena was unlikely to make the big time.

“I felt sorry for Marion. She had to be honest when she said to me, ‘I don’t think you’re all that special.’ In her opinion she just saw me as average singer.”

You are being generous there, Sheena.

“You have to bear in mind I was at drama school for three years, where every day directors would pull you apart, to make you improve. They would tell you when you were horrible.

“I remember once I had this scene in a Chekhov play and all I had to do was walk across the room, holding a candle. I did the scene and the director called out, 'That was the worst Natasha I have ever seen.' I wondered what I was doing wrong but later it dawned. My character was coming from somewhere and something had happened to me. I should have conveyed this. All I offered was Sheena Easton with a candle. So when I made The Big Time I was used to criticism. And I’m pretty good at taking awful moments and moving on.”

No sooner had Easton crashed the pop charts than she was offered the opportunity to sing the theme to For Your Eyes Only, beating Debbie Harry’s Blondie to the punch. To the outsider, there was more chance of Stanley Baxter becoming 007 than Easton becoming the next Shirley Bassey. How in the name of Miss Moneypenny did she pull that one off?

“I think it’s truly a case of the harder you work the luckier you get. It’s about having a steel rod up your spine, I guess. And it turns out [producer] Cubby Broccoli was a fan of my stuff, so he decided to go with me.”

Easton worked harder than even she could have believed possible. “I’d wake up and have no idea what day of the week it was. I remember once waking and having to look at the pad next to the phone on the bedside table, to see what language it was in so I could to work out which country I was in. It was in French, so I guessed I could also have been in Belgium or Switzerland.

“But I never thought to complain and say, ‘I haven’t had a day off in six months and I don’t want to go to Belgium tomorrow.'”

Easton admits to being a little affected by success. She bought a gorgeous Jaguar convertible – then realised she hated her hair being blown everywhere. “I thought, ‘Why did I buy a fricking convertible when you can only drive it with the top down?’” She now drives a Toyota Prius.

Money was important, however. She could “share it around, especially with my mom, and put some away”. Financial analysts (if they can be trusted) reckoned Easton was able to put away $40 million – or £32m – thanks to her 20 million record sales.

But if Easton was driven to succeed, in her thirties she hit the brakes, to “have a normal life” and despite being single (strikeouts on two marriages) adopt a boy and a girl. She stepped out of the spotlight and into a modest home in Nevada, having worked for years in Las Vegas.

“There’s never a sweet spot,” she says of finding the right work-life balance. “It’s feast or famine. Sometimes you work non-stop from January to July, then you have three months off and you want to shoot yourself in the face.”

The conversation is now warming. She’s more relaxed. Relaxed enough to talk about the Big Day, the 1990 concert in Glasgow Green? Easton, who has lived in the United States for 37 years, returned to Scotland with an El Paso accent and the crowd didn’t like it at all.

She smiles as she says most of the complaints passed her by. “I’ve heard they didn’t like my accent and I’ve often been told it was horrendous. It was certainly weird. And to this day, it changes. When I talk to my sisters it gets more Scottish. I guess I have one of those ears that picks up on accents. But what I won’t do, for example, if I’m coming back to Britain, is think, ‘I’d better brush up on my Scots.’ If I do that I tend to sound like Shrek’s mother.” At this she does a great Shrek-like Scottish accent.

Does she feel Scots are often too infected with tall poppy syndrome, all too quick to give the Lulus and Connollys a kicking? “Billy hasn’t had any real criticism, has he?” Oh, yes, Sheena.

Easton seems unaware of Scotland's skill in kicking our stars when they’re up, such as Connolly. Perhaps she’s being a little disingenuous. “Very early on, I learned the skill of avoiding what’s written about me.” But the singer can’t ignore a Sheena story when it’s particularly bad. “Sometimes I pee myself laughing when friends tell me I really need to look at a piece written about me, like the time a headline suggested I was ‘deathly’ when pictured in a wheelchair. It made me look like I was coming out of rehab.” In reality, she was coming out of the dentist. The wheelchair was an insurance safeguard.

Not surprisingly, she sticks to a small, supportive group of friends. “I’ve never been one for going to clubs and fancy restaurants. I’ve always kept my life insular.”

Not always, Sheena. Time spent with Prince in the late 1980s was fairly public. She sighs and reflects, “It was wonderful for him to send me a song he’d written and say in the note, ‘If you want to sing this, call me.’ I was thrilled. And I was shocked he had thought of me. He was just amazing.

“In those first few hours when we first met he poked fun at me, and being Scottish I loved the sarcasm. If you like someone you can be sarcastic towards them from the get-go.”

Easton maintains her dates with the diminutive pop genius produced nothing more sexy than hit pop songs such as U Got the Look and the saucy Sugar Walls. She’s very sad he’s gone.

“I hadn’t seen him much in the last years," she says. "I can’t picture him being gone. He was such a dynamo. And I can’t imagine how much pain he was in physically and emotionally for him to do what he did. But he was also incredibly spiritual, a great amalgam of so many things rolled into one.”

Now that her children are grown up, Easton is free to take on the West End. But what of relationships? The longest of her four marriages lasted 18 months. Is she still keen to become the happily married, domesticated woman she sang about in Nine to Five? “No. I’ll never get married again,” she says, emphatically. “You see, whenever I know something about myself I can’t un-know it.”

What does she know? “I’d go into a marriage thinking, ‘The last marriage didn’t work because of X, Y and Z.’ But then I’d start to think, ‘Well, you’re the common denominator in all of these relationships, so you are choosing people that there is no way in hell you are going to last with.' So I’d ask myself ,‘Why are you choosing them?’ And it’s because you know you don’t want to be in a permanent state. I feel hemmed in when I’m in a relationship. All of a sudden people assume you’re a couple and I hate the feeling when they say, ‘Why don’t you bring so and so with you?’ And I say, ‘Can’t I just bring myself?' I’m not a two, I’m a one.”

The lady is on a roll. “I don’t want a life where I’m interlocked. I hate the expression ‘the other half’. I’m not a half of anything. The only joining I’ve really made through choice is with my kids. I feel most at home, most comfortable being a mom.”

But there must be a romantic side to her, the optimist who has seen a ring placed on the third finger four times? “Yes, that’s why I’ve been married so often. I kinda do everything 100 per cent or not at all.” She offers a wry smile. “Look, I’m not saying that’s right or there’s anything smart about it. It’s just the way I’m wired. If I meet someone I tend not to date for a while. I fall in love and it’s wonderful and I get married. It’s only later I start to think, ‘I didn’t know this was coming along with the package’ and start to panic.”

It’s really not hard to see why Sheena Easton has become so successful. The early luck apart, she has a very good voice and she works like a machine. She’s very bright, and she has great cheekbones. But she doesn’t seem content, perpetually seeking something. Will she ever reveal all in a book? “It will never happen,” she maintains. “I don’t want to tell the story of other people’s lives because that’s an invasion of their privacy.”

As she rushes off to rehearsals she adds, smiling, “Who needs to read the story of another chick singer anyway?”

42nd Street is at the Theatre Royal, Drury Lane, London, from April 4.

Big moments on the Easton front

1979: Attends RSAMD; marries Sandi Easton

1980: Appears on BBC show The Big Time

1981: Sings the theme song to 007 movie For Your Eyes Only. Nine To Five reaches No1 in the US

1984: Marries agent Rob Light. Wins second Grammy

1985: Reaches No2 in the US alongside Prince with U Got the Look

1987: Appears on Miami Vice

1995/6: Adopts two children

1997: Marries film cameraman Tim Delarm

2002: Marries plastic surgeon John Minoli

2017: Returns to theatre