Items from Sir Elton John's vast collection of photographs - which he began buying after getting sober - are going on display at Tate Modern.
The 69-year-old star, who swapped his "alcohol addiction" for photography, owns about 8,000 images, dating from 1910 through to the present day.
Tate Modern is staging the first UK exhibition of Modernist photography from the singer's collection at its new Switch House extension.
The show features 191 photographs, including portraits, still life and experimental techniques, from the 1920s through to the 1950s.
Sir Elton said: "Collecting photography over the last 25 years has opened my eyes - it's one of the most important and progressive art forms of the 20th century.
"I want everyone to go away thinking about the artists behind these images and marvel at how they experimented and changed the way we see things forever.
"They were going where no other photographer had gone before. I consider them true adventurers and what they did was extraordinary.
"Many people may not even realise I have this collection. But art should be seen. That's why I'm so happy that Tate Modern is sharing these iconic works with the public.
"These photographs have given me so much pleasure for a long time and I hope visitors will experience as much joy in seeing the works as I have had in finding them."
In an interview published in the exhibition catalogue, Sir Elton told how he "suddenly became intensely interested in photography" and discovered it "as an art form" after leaving rehab in 1990.
"It's a much healthier addiction to buy photographs, so I just switched," he said.
"I felt as if my eyes were opened by photography. It was the most beautiful thing because I was getting sober, and feeling great about myself, and entering a new phase of my life.
"Photography became this incredible companion. It went hand in hand with my sobriety, which was also fresh and a release. I was like a kid in a candy store."
The star previously sold his Art Deco and Art Nouveau collection at Sotheby's.
He said: "I love objects. I've always loved objects. As a child, my parents argued a lot. So I found comfort in objects and my collections were always pristine, my records, my toys, they were all beautifully kept."
He criticised collectors who buy "trophy art", saying that "for me photography is a journey of discovery".
Tate director Sir Nicholas Serota said the singer - who set a record price when he bought Man Ray's Glass Tears at auction - showed a true passion for photography.
"Elton has shown a real commitment to photography as an art form. His passion is evident in the way he has built his collection, with images ranging from the male nude, to showbusiness celebrities, performers and musicians," he said.
"These reflect his natural sympathies but also make even more unusual and striking his commitment to the radical pioneers of the 20th century seen in the Tate Modern exhibition."
The exhibition is entitled The Radical Eye: Modernist Photography from the Sir Elton John Collection.
Sir Nicholas said: "We have called this show The Radical Eye to remind everyone just how original and challenging the pioneering photographers of the 1920s, 30s and 40s really were.
"Coming face-to-face with such masterpieces of photography in London will be a rare and rewarding experience."
:: The Radical Eye: Modernist Photography From The Sir Elton John Collection opens at Tate Modern on Thursday and runs to May 7 2017.