'In Dulci Jubilo' was not just Oldfield's first UK top five single, but has become a part of the sound of Christmas in his home country.
The upcoming exhibition will feature uncovered photographs and videos, original synthesisers, cassettes and vinyl.
The new expanded editions include a 48-page 12x12 book packed full of iconic photos, new interviews, liner notes and memorabilia.
Virgin Records co-founder Nik Powell and childhood friend of Richard Branson, Nik Powell has died in Oxford from cancer at the age of 69.
Unreleased at the time, the 'Out Of Control' mixes were recently unearthed when archive work began on the new, expanded edition of 1999's 'Surrender'.
The multi-instrumentalist found himself in the unusual position of seeing his second album replaced at the top by his first.
The band's high-profile third album, 'Surrender' featured vocals from Noel Gallagher, Mercury Rev's Jonathan Donahue, and Mazzy Star's Hope Sandoval.
Since this landmark debut, Harper has since released over 20 studio and live albums, including collaborations with Charlie Musselwhite, Mavis Staples and The Blind Boys of Alabama.
The albums' new editions include bonus discs featuring live and previously unreleased studio recordings.
The band's 40th anniversary and will be celebrated with a career box set and brand new greatest hits collection, 'Souvenir', on 4 October.
The special box set will comprise of 5 CDs and 2 DVDs housed in a 10” box set, together with a hardback book, poster and a series of 10” prints.
Coinciding with their 50th anniversary, it's curated by former member Steve Hillage and has the full involvement of original band members.
The releases are timed to coincide with the second run of Jackson’s 'Metamorphosis' residency in Las Vegas.
It was a tale involving an American hit that Oldfield didn’t approve of, a hit horror film, a complete rearrangement and Richard Branson’s sister.
The acclaimed singer-songwriter is also embarking on a full-scale UK tour throughout November and December.