When you’ve been in the business as long as Lulu has, you come to learn a few things. But it’s only now, in her seventh decade, that she has gained personal wisdom.

“I used to be manic, but now, not so much. I got older,” Lulu sagely explains down the line from her London home. “Everything’s changed in a way, yet nothing changed. Essentially, you’re the same person. Some of my rough edges have been smoothed off because I came from the wee part of Glasgow that I came from, and moved way up to mix with society types; rich, famous, educated people, which was not how I started.

“Some changes happen, and some changes you make happen. It’s all necessary.”

So far, so Zen. Lulu is now 67, and it’s fair to say that the bubbly singer who is prone to philosophical tangents and sudden bouts of the giggles has squeezed a lot of living into her life.

The woman born Marie Lawrie – these days officially known as Lulu Kennedy-Cairns, the "Kennedy" a nod to her mother's part-Irish heritage – has spent more than half a century as an entertainer since making it big with her debut single, Shout, in 1964. Famously plucked from working class Glasgow obscurity at 15, she was skyrocketed into a bizarre world of global hits, Eurovision triumphs with Boom Bang-a-Bang, James Bond themes (The Man with the Golden Gun), and all the rest.

Yet sacrificing her childhood for fame and fortune was never an option, Lulu says.

“Where I came from, it was a blessing,” she explains, a faint of trace of her Scottish accent remaining. “How much of an education was I going to get where I came from? What I’ve seen, where I’ve been, who I’ve been touched by . . . the education and the journey I’ve had, you couldn’t buy it, you couldn’t plan it.

“I made a record, and that was it. Oh my gosh, it was unbelievable the way things moved, and how I would say yes to things that I didn’t really wanna do, but was advised that it was a good career move. I would cry and I would feel like some of it was torture. But now I look at it, and I think, hmmm, well the sum of the whole thing means that I’ve had longevity. I’m here 50 years later, and nothing killed me. It almost did, but not quite,” she giggles.

These days, Lulu is happier than she has ever been. You can tell by the way she repeats the word. “Happy!” she squawks, presumably kicking up her feet and wiggling her hands as she yelps. “I’ve never been so bloody happy!”

This newfound contentedness may have something to do her recent flush of creativity. Over the years she has dabbled in everything from acting in theatre, TV and film, to writing two autobiographies and even launching her own line of beauty products, Time Bomb. Being known as Lulu the Singer, however, has always been a priority, and her new album, Making Life Rhyme (her first in a decade) saw her put pen to paper for the first time in her career.

"In a way, the music business is about young people. It's hard for an old fart like me, really," she chuckles. "When you're old, you have to really fight for your place, and I don't have a huge catalogue of amazing songs like The Eagles or Elton John. It's so hard to get anyone interested, and you think, well, what's the point? But I'd been doing some blues clubs in America and here, and the musicians kept going on at me about doing an album. I said okay, nobody will ever buy it, but let's do it, because I'd enjoy it.

“Then I wrote a couple of songs with my brother Billy that we sent in – with a whole bunch of other songs – to Decca, and they said [that they] like the new ones better than the old ones, so that’s really what happened. I got the best write-ups that I’ve had in my entire career.”

It is true that Making Life Rhyme has been well received, but the actual process of writing also contributed to Lulu's current sense of self-fulfilment. Growing up in what she describes as a turbulent household, where both parents were physically violent with each other, has had a lasting effect on her. So writing was therapy, in a way.

“When I was younger, I never wanted to let people know who I really was,” she says. “I was one of those people who thought that if I said I didn’t know something, I would be considered stupid, or an outcast. So I would somehow try not to do that, because I thought that I had to be perfect. There was a lot of love [in the family], but it was an extremely turbulent environment.

“So by the time I started to become successful as a singer, being the eldest, I made the money and I took care of my family and I was always very responsible. Then I had people on the payroll, so I was responsible again, and I felt that I had to keep it up. So I was afraid to really reveal myself. But when you write songs, you have to reveal something of yourself.

“I’ve now come to a point where I’ve had to deal with certain issues in my life. I’ve been told that I have PTSD, post-traumatic stress disorder. I said, ‘How can I have that? That’s what you get when you’re in Afghanistan!’ And they said, ‘Well, your childhood was a warzone, that’s why you have always been anxious all your life, and that’s why you did this and felt that way, etc.’

“So that gave me more fodder to write – and also, it gave me more humility. I realised that I don’t have to be perfect; the key is to be just me. I was late on finding who I am – and being bloody happy. I’ve had flashes of real happiness, but now? It’s kind of like I’ve been given a second chance. My life is a miracle.”

In the midst of finding herself, Lulu's love life has been as colourful as her career. When she was 20 she married Maurice Gibb of The Bee Gees, but they divorced four years later. She's alluded to an innocent dalliance with Davy Jones of The Monkees and a fling with collaborator David Bowie in the 1970s. Her second husband was celebrity hair stylist John Frieda in 1977, father of her only child, Jordan.

Lulu's career has been one of peaks and troughs, as well, with stretches spent both in the limelight and in the shadows. Life was comparatively quiet, for example, in the early 1990s, But then she featured on a cover of Dan Hartman's disco classic Relight My Fire with Take That. The song introduced Lulu to a new generation of pop fans in 1993.

"I was like, are you kidding? Why would I do something with those little boys? I'm in my 40s and they're practically in their teens!Then they said they want to do the old Dan Hartman song, Relight My Fire. I said oh, I love that song – but, y'know, the original has this fantastic black diva. I can't copy that. Their manager said you try it out; if you like it, it goes out, and we won't release it if you're not happy with it. And the rest is history, really."

She remains as confident as ever in her abilities, but how would 15-year-old Lulu fare in today's X Factor and Voice-obsessed music industry?

"I listen to some kids these days, and I think God, I would never stand up to them," she chuckles. "But then I've said that to a few people, and they've said, if you were born in this day and age, oh yes, you would have. I've always had the drive. I was never sure of myself when it came to boys, and I never had an education. But I did know that I could cut it when I opened my mouth to sing. So I would have been listening to those Mariah Carey riffs and Christina Aguilera riffs a zillion times a day, and I would have nailed them."

She names Bruno Mars as a particular current favourite, and says it's fantastic that Sam Smith ("he sings like an angel") has been chosen for the latest Bond theme.

"You listen to Ed Sheeran sing Thinking Out Loud and it's Van Morrison to me," she says. "He's just brilliant. Way back in the old days there were great entertainers, and I think Beyoncé and Bruno are the greatest entertainers in the world today."

Considering the legendary figures she has worked with and the number of stories she has to tell, it is no small thing for this young generation to be lauded by Lulu. Despite her achievements and ongoing success, she remains as hungry as ever.

“I am still ambitious, but I’m not running,” she agrees. “I’m ambitious to keep on doing this until I drop. And to keep enjoying it until I drop.”

And as for her crowning achievement? Can her long and illustrious career possibly compete with finding personal tranquillity, or with the satisfaction of being a good mother and now a grandmother of two? What would Lulu like to be best remembered for? For the first time, she doesn’t jump in with a swift, impassioned answer.

“Oooh, I dunno. That’s a very good question.” She pauses. “Maybe just for people to say ‘Y’know, there was more to her than I thought.”

Perking up, Lulu throws her head back and emits another of those fantastically infectious giggles.

“Know what I mean? ‘There was more to her than she let us see.’”

Making Life Rhyme is out now on Decca. Lulu plays Belfast's Waterfront Hall on October 10th; Dublin's National Concert Hall on October 11th; and the Mount Errigal Hotel, Letterkenny, Co Donegal on October 13th