'Elvis Presley: The Searcher (The Original Soundtrack)' is to be released on April 6.

The CD accompanies the forthcoming two-part HBO documentary of the same name, and contains rare treats for fans of the late King of Rock 'n' Roll, including a version of 'Wooden Heart' by the late Tom Petty and the Heartbreakers and 37 different cuts from the music icon.

Pearl Jam guitarist Mike McCready's original score is also featured on the three-disc LP, which is comprised of Elvis' biggest hits and various remixes of his works from his two-decade career.

The director of the movie, Thom Zimny, writes in the pack cover: ''The soundtrack was in my mind from the beginning. I wasn't just making a film, I was thinking about the collection of recordings I would gather for a person who saw the film, who wanted to complete the experience, just as I always had. Thankfully, our friends at Sony gave me and the Searcher team the chance to create this collection. It's been in my mind for years now. To me, this collection is part of the film.''

The documentary features some of the 'Jailhouse Rock' hitmaker's dearest friends, including Petty - who sadly passed away in October from an accidental drug overdose - who said the world needs to admire Elvis for his ''beautiful and everlasting'' music.

He says: ''You know, God bless him.''He was a light for all of us. We all owe him for going first into battle. He had no road map and he forged a path of what to do and what not to do.

''And we shouldn't make the mistake of writing off a great artist because of all the clatter that came later. ''We should dwell in what he did that was so beautiful and everlasting, which was that great, great music.''

And Bruce Springsteen says: ''You hear performers in the thrall of the beauty of invention, not knowing quite where they're going to go, not knowing exactly what they're doing.

''Just discovering and doing it literally as the music is being played .... You're out on the frontier and it's a very pristine and exciting place to be.''

The film, which will premiere in America on HBO on April 14, uses rare footage lensed throughout Elvis' life and career as a means of exploring the musician's singular musical vision in all its complexity.

The 3CD set - which will be released on Legacy Recordings, the catalogue division of Sony Music Entertainment, and RCA Records - includes a 40-page hardcover book featuring rare photography, liner notes by Warren Zanes, and a director's note by Zimny.

'Elvis Presley: The Searcher (The Original Soundtrack) - CD/Digital' CD 1 tracklisting is as follows:

1. 'Trouble' / 'Guitar Man'

2. 'My Baby Left Me'

3. 'That's All Right'

4. 'Baby Let's Play House'

5. 'Heartbreak Hotel'

6. 'Lawdy, Miss Clawdy'

7. 'Hound Dog'

8. 'Crawfish'

9. 'Mona Lisa'

10. 'Milky White Way'

11. 'Like A Baby'

12. 'Are You Lonesome Tonight?'

13. 'It's Now Or Never'

14. 'Tomorrow Is A Long Time'

15. 'Suspicious Minds' (take 6)

16. 'Separate Ways' (rehearsal version)

17. 'Hurt' (take 5)

18. 'If I Can Dream'