“It's astonishing to me that nobody knows anything about him, and it baffles me,“ says Eric Clapton as the JJ Cale tribute album is released on July 29.

“ I wonder, 'What is it about his stuff that gets to me that nobody else is hearing?' I don't know. I still don't understand that."

Eric Clapton and Friends: The Breeze, An Appreciation of JJ Cale will be released on July 29 and will feature reinterpretations of 16 Cale tracks, sung by Tom Petty, John Mayer, Willie Nelson and Mark Knopfler and others.

 In 2006, Clapton and Cale released a CD of collaborations and duets, entitled The Road to Escondido. According to Clapton, recording with the Oklahoma-born musician was "the realisation of what may have been my last ambition, to work with the man whose music has inspired me for as long as I can remember.”

Cale wrote the songs After Midnight and Cocaine, both of which were massive hits for Eric Clapton and continue to be popular stage favourites.

Clapton dreamed up the idea for the tribute album on the flight to attend Cale's funeral in August 2013 in Escondido, California. "It just seemed to be a logical progression I would do," Clapton explains.

"I was aware of the fact that he's better known in Europe and in the rest of the world than he is in America. That's a bad thing, but it also means I have an opportunity to introduce people to him beyond (the Cale songs) I've recorded.”

He has more Cale compositions that he wants to record.  "I don't know how (Cale) would feel about it, to be honest, because some things are finished and some things are kind of half-finished,"  the musician explains.

"Some things are incredibly intimate that he might be embarrassed about or whatever. But I think when you're gone, it's good to have people still find stuff like this to listen to. It keeps it alive." Clapton performs Call Me the Breeze in Basel in November 2013 here: