An 'Imagine' boxset is being released to mark what would have been John Lennon's 78th birthday.

On October 5, four days before the Beatles legend's birthday, Universal Music are releasing six-disc 'Imagine - The Ultimate Collection', which was unveiled today (23.08.18) with the release of the raw piano demo of Lennon's best-selling song of his solo career, which he co-wrote with and was inspired by Yoko Ono Lennon, the 'Woman' hitmaker's widow.

Yoko says in the preface of the 120-page book that accompanies the boxset: '''Imagine' was created with immense love and concern for the children of the world. I hope you enjoy it.''

The remixed and remastered 140-track collection, which contains songs spanning the music icon's solo career, is fully authorised by Yoko, 85, who oversaw the production and creative direction, and is spread across four CDs and two Blu-ray discs.

Fans are taken on an ''incredible journey'' documenting the entire process of making the 1971 classic, from the writing and recording at Lennon's very own Tittenhurst Park studio space in Ascot to the co-production by Phil Spector.

The press release announcing the boxset reads: ''This is the first time that this iconic album has been explored and presented so completely. It's a long-overdue and fitting tribute to one of the most important songs, albums and creative collaborations of the 20th century.

''John & Yoko's message is as universal and pertinent today as it was when the album was created and arguably needed more now than ever.

''This new edition takes listeners on an incredibly personal journey through the entire songwriting and recording process - from the very first writing and demo sessions at John's home studio at Tittenhurst Park through to the final co-production with Phil Spector - providing a remarkable testament of the lives of John Lennon and Yoko Ono in their own words.''

As well as the boxset, Eagle Vision are releasing two films by Lennon and Yoko, 'Imagine' and 'Gimme Some Truth', on DVD, Blu-ray, and digital platforms.

Both films have been hand-restored from the original film reels and remastered in HD, and their soundtracks have been remixed in surround sound by Grammy-winning engineer Paul Hicks. Both physical releases feature exclusive, never-before-seen extras including previously unheard raw studio mixes, and a fascinating insight into a photo shoot with celebrity photographer David Bailey.

Yoko was awarded a songwriting credit on 'Imagine' by the National Music Publishers Association last year.

A video message from 1981 from Lennon - who was shot dead by Mark David Chapman in the archway of the Dakota, his residence in New York City on December 8, 1980 - was aired at a ceremony in which he said Yoko was deserving of a co-writing credit because of the ''influence and inspiration'' she provided for the lyrical content.

'Imagine: The Ultimate Collection' is available to pre-order now.