IMELDA May has been around the block enough times to know that the final stages of writing a new album can be fraught with self-doubt. It helps to have an old friend to call on. When that friend is the lead singer in one of the biggest bands in the world, it helps a lot. Enter Bono, who became a crucial “mentor” during the making of May’s latest record.

“He became a really good confidante, someone to lean on,” says the Irish rock and roller. “We were at a charity event where his wife was getting an award, and he said, ‘It can get tough making decisions, we all need someone who gives us the truth and speaks their mind. If you want me to do that I’m happy to.’ I thought that was great, but I didn’t think of it again until I got really stuck. I didn’t know which songs were going to make it on the album, and he was great. He kept me focused and guided me: ‘What is it that you really want to do?’” She laughs. “I was getting rid of a song and he said, ‘You just haven’t finished it. Finish the bloody song!’”

The tough love paid off. It’s as unwise to judge an album by its cover as it is a book, yet the title of May’s fifth album says it all: Life. Love. Flesh. Blood. “I always go with my guts and my heart, and I’ve definitely worn my heart on my sleeve on this album,” she says, in a Dublin accent that could slice through steel. “I’ve made the album that I needed to make. I’ve put it all out there.”

Written and recorded following the break-up of her 13-year marriage to Darrel Higham, the English musician who was also the guitar player in her band, Life. Love. Flesh. Blood. significantly advances May’s sound. There have always been elements of blues, jazz, gospel and country in her music, but now those influences are more overt, more emotive, and worn more elegantly. Produced by roots avatar T-Bone Burnett and featuring contributions from Marc Ribot, Jeff Beck and Jools Holland, it is the finest work of her career. Just don’t call it a heartbreak album.

“People hear one thing about your life and make assumptions,” says May. “They hear, ‘Oh, she’s after getting divorced, it’s a break-up album.’ Tie it up in a nice bow and we’re done. There is heartbreak in it, but it’s not a heartbreak album. I wrote it over the course of a year and a half, and I wasn’t sitting there crying over a piece of paper for the whole time. Lots of things happened, and I write about them: you meet someone else, you have a great time and you feel good, so you write about that. There’s desire, lust, guilt, all that lovely Catholic stuff going on. I think the album goes full circle, really. It’s like a year in a life.”

It was, she felt, time for a change across the board. As well as being her husband and the father of their five-year old daughter, Higham was also a key member of May’s band. She insists the musical fall out from their split was only positive. “I’ve been in bands doing this for 25 years,” says May, who started singing in Dublin clubs when she was still too young to drink in them.

“I’m 42. Darrel and I were only in the same band for seven years, and we’ve never written together. People presume when you’re married that you write together, but we didn’t. Even before the last album, he wanted to set up his own band and write again. So I didn’t find it daunting, I found it exciting for both of us. You have to be able to keep moving.”

With the release of her last album, 2014’s Tribal, May knew instinctively that she had taken her punky rockabilly aesthetic as far as it could go. She had become to feel constrained by its limitations and pigeonholed by her retro image, her penchant for 1950s-style patterned pencil dresses and bequiffed hair style. Having returned with a more “natural” look, May has discovered to her chagrin that the distinctive blonde quiff, in particular, dies hard.

“Isn’t it funny?” she says, in a voice which suggests it isn’t funny at all. “You get sick of talking about your hair so you change it so everyone will leave you alone, then everyone wants to talk about you changing your hair. Oh, the irony! It’s not a big strategy, like Madonna: new album, new life, new look. I just felt like a change. I wanted to go back to basics with everything. People have preconceived notions of you, and I wanted it all to stop. I wanted to just write and see what happened. For the songs to lead me, almost.”

She wrote almost 40 songs for the record. Following Bono’s advice and encouragement, May’s next coup was getting T-Bone Burnett to produce. The Texan has an impeccable roots pedigree, with credits ranging from Elvis Costello’s King of America to Raising Sand, the landmark 2007 collaboration between Robert Plant and Alison Krauss. The pair had, it transpired, been circling each other from a distance for some time.

“T-Bone said, ‘I was aware of you, I was watching you, but you weren’t ready for me then. You’re ready now.’ I thought that was fabulous. I wanted his classy bad-assed-ness. He’s open minded and creative, and I wanted all of that. I was delighted when he said yes.”

Under Burnett’s energetic supervision, Life. Love. Flesh. Blood. was recorded in seven days in Los Angeles, using the same stellar band of session musicians who had played on Raising Sand.

“We all met up on the first day and it was just beautiful,” says May. “T-Bone gets the right people in the right place at the right time, and then he lets it go. We recorded 15 songs in seven days – not because we had to, but because it just worked. There was electricity in the room.” She has special affection for Ribot, the bohemian New York guitarist who has added sharp, idiosyncratic angles to the music of, among others, Tom Waits, Debbie Harry and Costello. “A wonderful man and a great mind,” says May. “He can talk about everything from James Joyce to Himalayan chants.”

Older friends added their own distinctive touches. Holland contributed piano, while Jeff Beck added a weeping solo on the bluesy torch song, Black Tears. Both were instrumental in bringing May to wider prominence almost a decade ago; now she feels she has repaid the favour. Life. Love. Flesh. Blood. is an impressive coming of age. She is rightly proud it, while admitting to feeling nervous at putting so much of herself on the line. “It’s scary, but you just have to be true and real, and then hold your breath and hope for the best. You have to own your own failures and your own successes, whichever way it goes.”

Life. Love. Flesh. Blood (Decca) is out today. Imelda May plays Usher Hall, Edinburgh, on May 23 and Royal Concert Hall, Glasgow, on May 24