The term 'ANY OF THE FAB FOUR' is a reference to the Beatles, a British rock band that formed in 1960 and became one of the most successful and influential musical acts of all time. The answer to the crossword clue BEATLE (6 letters) is therefore 'BEATLES'. The Fab Four were John Lennon, Paul McCartney, George Harrison, and Ringo Starr. They released a series of highly successful albums and singles, and their music continues to be popular today.