Image courtesy of Sony Pictures Classics.

In February, Sony Pictures Classics opened a window into the inception of one of the greatest bands of all time with Becoming Led Zeppelin. The legendary heavy metal innovators’ first-ever officially sanctioned documentary chronicled their early years and ascent through archival materials and first-hand accounts from the iconic quartet, earning an outpouring of critical acclaim and a record-breaking opening weekend for IMAX®-exclusive music features. Today, on top of the wealth of long-lost rarities compiled for the original release, the film has unveiled an exclusive Encore: a never-before-seen 15-minute performance of “Dazed & Confused,” captured live in Amsterdam in 1969.

The mythical footage from Led Zeppelin’s origins, unearthed after more than half a century on the shelf, captures the irrepressible creative fervor that possessed Robert Plant, Jimmy Page, John Paul Jones and John Bonham from the outset. The full concert film is included in the newly announced Becoming Led Zeppelin Limited Collector’s Edition SteelBook, set to release on Sept. 30.

Available to pre-order exclusively via Relix, the documentary’s deluxe packaging houses 4K UHD + Blu-Ray discs of the film in an archival-grade SteelBook case, printed with original artwork. Other featured memorabilia includes a printed letter from director Bernard MacMahon on the film’s incredible story, four archival photograph cards, an iron-on patch, a vinyl sticker and guitar picks emblazoned with logo art. The limited-edition Relix preorder is also the only opportunity to secure an official replica ticket for the Becoming Led Zeppelin premiere at Hollywood, Calif.’s iconic Grauman’s Chinese Theatre, commemorating the film’s titanic $3 million opening.

Becoming Led Zeppelin arrived as the first account of the band’s history in their own words through passionate efforts by MacMahon and writer/producer Allison McGourty, who spent years assembling a towering psychedelic tribute from live footage, unearthed home movies, current interviews with the musicians and more. To create this unprecedented view into the group’s origins, the team scoured the globe to recover early materials long thought to be lost or nonexistent, including tape from 1969 concerts at the Atlanta Pop Festival, the Fillmore West, and the Texas Pop Festival and an unreleased interview with the late John Bonham.

“We spent five years flying back and forth across the Atlantic scouring attics and basements in pursuit of rare and unseen film footage, photographs and music recordings,” McGourty shared in a statement. “Then we transferred each piece of media with custom techniques, so that in IMAX, these 55-year-old clips and music would look and sound like they came out of the lab yesterday.”

Watch exclusive teasers from Led Zeppelin’s never-before-seen set from Amsterdam in 1969 below. Secure your copy of the Becoming Led Zeppelin Limited Collector’s Edition SteelBook while supplies last, only at relix.shop.