Bruce Springsteen has released 'Adelita,' a previously unheard song from his shelved 1990s album Inyo.

The track is a solo acoustic piece featuring mariachi instrumentation and honouring Mexico’s "soldaderas." These were women who fought in the country’s independence struggles during the Mexican Revolution.

The song draws inspiration from the traditional corrido ballad 'La Adelita.' Although mostly a solo project, the track features a variety of mariachi musicians including Luis Villalobos, Alberto Villalobos, Angel Ramos, Humberto Manuel Flores Gutierrez, David Glukh, Jorge Espinosa and Miguel Ponce.

The full 10-track LP will be out on June 27 as part of the singer's collection of unreleased material Tracks II: The Lost Albums.

The compilation will include a total of seven albums including Streets of Philadelphia Sessions and Faithless. The box set will be available in vinyl, CD and digital formats, accompanied by a 100-page book with archival photos and essays.

'Adelita' follows earlier previews like 'Rain in the River' and 'Blind Spot,' which offered fans a glimpse into Springsteen’s longtime secret vault of material.

"Inyo was a record I wrote in California during long drives along the California aqueduct, up through Inyo County on my way to Yosemite or Death Valley,” recalls Springsteen.

"I was enjoying that kind of writing so much. On The Ghost Of Tom Joad tour I would go home to the hotel room at night and continue to write in that style because I thought I was going to follow up  with a similar record, but I didn’t. That’s where Inyo came from. It’s one of my favourites."

You can check out 'Adelita' below: