Unseen Elvis Presley footage film unveiled by biopic director Baz Luhrmann

Following the release of Elvis, Baz Luhrmann is now working on a brand new documentary film on the King.

Much like Peter Jackson's retrospective The Beatles: Get Back, Baz has had access to a ton of unused footage from the classic Elvis documentary films.

These include the 1970 Las Vegas residency concert movie Elvis: That's The Way It Is and 1972 concert road film, Elvis on Tour.

The filmmaker unearthed the unseen negatives when Warner Bros allowed him to dive into their underground salt mine vaults in Kansas while he was researching his biopic.

Also among the treasure trove was rare behind-the-scenes audio that had been feared lost, including recordings of Elvis telling stories about his life.

Now, Baz has announced the documentary film will be called EPiC: in Concert.

The 62-year-old posted previously unseen footage of the King on his Instagram and captioned a post: "What an experience last night at the Sony Music Vision Content Showcase!!! Starting with a wonderful sneak of the Barbra Streisand project by Frank Marshall and a dazzling Lisa documentary by Sue Kim. But of course, the one and only Elvis, closing out the show to rapturous applause!! EPiC rocked the house - I thought I'd share with you all what I said last night..."

Baz continued: "During the making of ELVIS, we went on a search for rumoured unseen footage from the iconic 1970s concert films Elvis: That's The Way It Is and Elvis on Tour. My initial thought was that we may be able to restore the unused footage (if we could find it) and use it in our Elvis feature, starring Austin Butler. I had researchers go into the Warners Bros film vaults buried in underground salt mines and, to the astonishment of all, we uncovered 68 boxes of film negative, as well as unseen 8mm footage. It has taken two years to restore the footage to a quality that it has never been projected at previously, while the team had to meticulously claw back sound from the many, unconventional sources that were also unearthed. One of the great finds has been unheard recordings of Elvis talking about his life and his music. It was this that gave the inspiration for EPiC: Elvis Presley in Concert, which is not specifically a documentary, nor a concert film: Elvis takes the audience through the journey of his life, weaving never-before-seen footage with iconic performances that have never been presented in this way, from the 1970 Vegas show, on tour in 1972 and even precious moments of the 1957 gold jacket performance in Hawaii. Most importantly, Elvis will sing and tell you about his life in first person, through both classic and contemporary musical prisms."

EPiC: Elvis Presley in Concert is set to release later this year.