X The Unknown Limited Collectors Edition 4K Ultra HD + Blu-Ray (Region Free)

2026 marks the 70th anniversary of this suspenseful science-horror classic from legendary writer Jimmy Sangster, as X the Unknown makes its worldwide 4K premiere. Widely regarded as the “missing chapter” of the Quatermass series, this landmark film has been newly restored by the teams at Hammer and Silver Salt Restoration.

When a soldier dies from apparent radiation poisoning, the Atomic Energy Commission dispatches scientist Dr. Royston (Academy Award® winner Dean Jagger) to investigate. Despite extensive testing, no source can be identified—until a mysterious, radioactive, mud-like entity resurfaces and begins claiming more victims. What do you do when the threat cannot be stopped—or even understood?

Limited Edition Contents

This premium edition includes:

• Four-disc set housed in a stylish digipak (2 x 4K UHD + 2 x Blu-ray), with Hammer content duplicated across both formats
• Three versions of the film:
  • 1.66:1 UK Theatrical Version (widescreen)
  • 1.37:1 As-Filmed Version (fullscreen)
  • 1.85:1 US Theatrical Version (widescreen)
• Subtitles: English, French, Italian, Spanish, German (all versions)
• Brand-new 5.1 audio mix for the 1.37:1 and 1.66:1 versions, alongside the original mono soundtrack
• High-end leather-feel slipcase
• Rigid inner box featuring new artwork by Robert Sammelin
• Double-sided poster featuring original one-sheet artwork
• Eight art cards reproducing original cinema lobby cards
• 120-page booklet featuring new essays, production insights, cast/crew bios, script comparisons, and more

Special Features

• A Man on the Beach – Rare early Hammer short film written by Jimmy Sangster and directed by Joseph Losey
• New audio commentaries featuring:
  • Toby Hadoke & Andy Murray
  • Dr. Steve Haberman & Constantine Nasr
  • David Kalat
• Archive 2003 commentary with Jimmy Sangster & Marcus Hearn
• Commentary on A Man on the Beach by Neil Sinyard
• New documentary on the making of X the Unknown
• New documentary on special effects pioneer Les Bowie
• Documentary on Joseph Losey and his involvement with the project
• Sidebar: X the Unknown – discussion with Tim Lucas & Stephen R. Bissette
• Archive Jimmy Sangster interview (2003)
• Original trailers, censor card, and Super 8 cut-down version
• Extensive stills and publicity image gallery

Technical Specifications

• Audio: English Mono / 5.1
• Discs: 2 x 4K UHD + 2 x Blu-ray
• Region: UHD Region Free / Blu-ray Region ABC
• Rating: PG
• Runtime: 1 hour 20 minutes
• Subtitles: English, French, Italian, Spanish, German