They performed one of the most iconic duets in music history at the 2004 Grammys, and now Beyonce has revealed just how much Prince meant to her in a new book.

Prince passed away on 21 April 2016 at the age of 57 following a self-administered overdose of the powerful painkiller, fentanyl. At the time of his death, the 5ft 3in singer weighed just 112lbs, according to the autopsy report.

The Purple Rain crooner is the subject of a new book of photographs by his close friend and longtime photographer, Afshin Shahidi, which comes complete with a heartwarming message from Beyonce.

According to Entertainment Weekly, Queen Bey's foreword simply reads: "Truth be told, the word 'icon' only scratches the surface of what Prince was and what he remains to me."

Shahidi captured Prince's performances and most private moments for a decade and the tome, Prince: A Private View, features photos and captions which reflects that relationship.

In 2011 Beyonce joined Prince on stage at the 46th Annual Grammy Awards in a sparkling pink dress to perform a medley of his greatest hits and a funky rendition of her hit, Crazy in Love. He famously ended the set telling the star-studded audience: "Don't hate us cuz we fabulous," before throwing his guitar and dramatically walking off stage.

The trailblazer later praised Beyonce as 'talented' when asked about working with her in the run-up to the show. "I was curious to how much she knew musically and I was really pleased to find out that she knew a lot about scales, Mixolydian scales, and Egyptian style and different things like that, I was just trying to show her some chords on the piano and help her to respect the fact that if she learns piano a la Aretha Franklin and Ray Charles and things like that I mean the skies the limit as to what she could do because she's so very talented."

In the aftermath of Prince's death, Beyoncé paid a musical tribute to the icon by singing The Beautiful Ones and Purple Rain during her Formation tour.

Prince: A Private View is scheduled for publication on 17 October.