As he prepares to re-release his Fab Four photo book, Photograph, later this month (Sep15), the drummer has started thinking about a follow-up - but he admits he needs a little help from his friends.

Starr is asking MCCartney, Yoko Ono and Olivia Harrison to explore their personal photo archives for negatives and rare snaps.

During a new exhibition of images from his 2013 book at the National Portrait Gallery in London, the drummer told reporters, "If they're listening... dig out the negatives...

"The other boys had cameras too, so the next plan is I want to get the rest of my pictures - Paul's pictures; Yoko will have John's pictures, Olivia, George's. It would make a great book. I'll be in a lot more photos... If I put it out there, they might respond."

Starr tells Britain's The Guardian he discovered a treasure trove of Beatles photos while digging through a storage facility.

He says, "I had a lot of stuff in storage, and we had to move everything, and I started finding books of negatives, a lot of them I didn't know I still had."

His new book features 250 unseen shots of the Beatles in the studio, on tour and on vacation.