Emerson, Lake and Palmer Singer Dead at 69

Greg Lake, who co-founded the popular progressive rock band Emerson, Lake and Palmer ... died Wednesday.

Greg's agent said he died after "a long and stubborn battle with cancer." Greg is the second member from the '70s band to die in 2016 -- founding member and keyboardist Keith Emerson died back in March.

ELP burst onto the scene in 1970 at the Isle of Wight Festival ... where Jimi Hendrix and The Who also famously headlined. The band broke up off and on and reunited for a tour as recently as 2010.

Greg also had a successful solo career that included the 1975 classic, "I Believe in Father Christmas."

He was 69.