In the days before digital, a photographer would send physical prints to the magazines and newspapers they worked with. Those prints would be scribbled on, marked up, captioned — and frequently tossed or forgotten. Fortunately, British celebrity photographer Terry O’Neill saved pretty much every scrap of paper.

“I just kept everything,” says O’Neill of a storied career that stretches back to the 1960s. “I don’t know why. Back then, there wasn’t really a reason to keep them. Photos were used straight away, and then I just moved on to the next assignment. No one was thinking these would be worth anything down the line, let alone 50 years later.”

He has compiled some of those images in a beautiful book called “Rare and Unseen” (Acc Art Books), out now.

A flip through its pages reveals celebrities seen through a different lens: relaxed, often playful. Julie Andrews poses in a sexy off-the-shoulder bathing suit on the set of “Star!” in the South of France, looking far worldlier than her “Sound of Music” character, Maria.

A growling John Cleese surrounds himself with taxidermied skunks and cats in a 1997 publicity shot for “Fierce Creatures.” A jubilant and achingly young Paul McCartney sits and plays the piano during an impromptu entertainment session at Ringo Starr’s wedding reception in 1981. “Terry’s photographs have a language all of their own,” notes Raquel Welch in the book foreword. “It’s a conversation between lens and subject without the use of words.”