The powerful soulful voices of married couple Michael Trotter and Tanya Trotter-Blount, known as The War and Treaty, just won't go away.

After a stunning debut at Bluesfest in April this year, they are already on the line-up for 2020 Bluesfest.

It's hard to believe this pair have only come into focus. While their back story is romantic and emotional, they have been paying music dues for a long time.

While both have gifted voices, crafted from childhoods flooded with the sounds of soul and '60s pop, they also have a gift for songwriting. When they finally arrived on the main stages of America last year, they came equipped with plenty of talent.

Michael Trotter's back story tells of a shy, poverty-stricken childhood, eventual enlistment in the US Army and being shipped off to serve in the Iraq war in 2003.

Trotter was fortunate to become befriended by an officer who realised Trotter was not meant for fighting, but had a gift for making music, which he nurtured - while the American soldiers encamped in a Saddam Hussein palace with an abandoned piano.

After the war, Trotter pursued a career in music, which led to him meeting Tanya, at a festival in 2010. They fell in love, made music, had a child (a son, Legend, eight years old) and began their passionate journey.

Tanya was born to sing: she had an early taste of success, landing a role in Sister Act 2 singing a duet with Lauryn Hill (His Eye Is On The Sparrow). Yet, all the hard work never and adventures in various genres didn't pay off until the songs she made with Michael caught fire.

And to be clear, together they drove a lot of miles before they found traction. You can get a lot of mileage out of love and music.

"The success hasn't changed our relationship," Trotter-Blount says. "We just bought a house in Nashville. Four or five years ago we were homeless, rehearsing on a Casio keyboard with four DD batteries.

"We go back now and reflect on those moments. We love music just as much now, we're just playing on a larger platform."

The change in fortunes came when Americana producer Buddy Miller came on board, and produced their debut album, Healing Tide, as The War and Treaty, released in August 2018. They've been playing major festivals since.

"We moved to Nashville and bought a house 17 months ago," Trotter-Blount says. "But we've only been home for two weeks."

Their sound is sooo catchy, like an ice-cream cone stacked with 10 scoops. You can hear so much musical history in each song, it triggers memories and gives you a craving to dig up your own musical history, especially if you're over 50.

Trotter-Blount embraces the influences.

"We listen to a lot of different styles of music," she says. "We're are fortunate to have so many artists come before us. We are preserving of our history: we take and put it to our music. Consciously or unconsciously. Ray Charles, Aretha Franklin, Johnny Cash, Dolly Parton. You can't help but allow their sound to get in your bloodstream It may show up without your bloodstream even knowing it.

"I compare it to growing it up under same roof as mum and dad. Sometimes you have a moment, when you think, 'I'm so much like them . . .

"It's the same as music.

"Studying it, in spirit. It will come."

The music, combined with their personal warmth, has made them crowd favourites. Though he suffers from war-related PTSD, Michael has aided the building of a fan base through constant social media activity and a sizeable following of war veterans.

It all comes naturally to Tanya.

"When I was a child, I used to go to school dressed up like Tina Turner," she says. "I'd take my mother's wigs and make them into Dolly Parton. I went to a public school.

"One day my dad came home and said take her out of there. And they put me in a performance arts school with all the other weirdos. I felt right at home."

By the time the reach Bluesfest in April 2020, they should have a new album to sing about.

Blount-Trotter says the duo are heading into the studio in about five weeks with a bundle of new music - Michael Trotter writes songs every day.

The new album already has a working title, "Heartstown", which she says is a term the two use for where their headspace is at these days.

"Our music has evolved from Healing Tide," she says. "Healing Tide was a washing away, talking about some of the things we have to go through.

"Heartstown is a neighbourhood we created in our heads. For those silly enough to believe. For the people out there with compassion, empathy, love and not afraid to show up."