Eric Clapton: Sorry, Layla ... This Guitar Is for Another Woman

Eric Clapton's personal guitar is heading to auction and is expected to raise a ton of cash for a fellow musician.

Eric's 2014 Fender Stratocaster -- the one he played at his 70th Birthday Celebration Concert -- is being hawked by Johnny Nicholas, of classic country group Asleep at the Wheel, through Heritage Auctions. We're told it's estimated to go for more than $20,000!

The guitar's sale was intended to benefit Johnny's wife, Brenda -- who had been fighting Leukemia -- but, sadly, she passed away a few weeks ago. All proceeds will now go toward Leukemia research.

The Strat is signed by Slowhand, and you can put in an online bid now or get to Dallas for the live auction on July 23.