The late sticksman for The Who - who died of a drug overdose on September 7, 1978, when he was just 32 - made no secret of the fact he was a huge fan of the surf rock legends, and he even put pen to paper offering his services to the 'Good Vibrations' group, according to co-founding member Mike Love.
However, they turned him down because they were faithful to their drummer Dennis Wilson - the middle brother of former member Brian Wilson and late guitarist Carl Wilson - who tragically drowned to death at the age of 39 in 1983.
Speaking at an album playback and Q&A of their new LP, 'The Beach Boys With The Royal Philharmonic Orchestra', at Spiritland in Kings Cross, London, on Wednesday (13.06.18), Mike recalled: ''He wrote us a letter saying he wanted to be our drummer, but unfortunately Dennis Wilson was our drummer.
''Dennis, Brian and Carl and Al wouldn't have allowed it. ''
The Who's frontman Roger Daltrey, 74, previously revealed how much of a fan of the 'Kokomo' hitmakers his bandmate were, and how Keith was willing to quit the 'Pinball Wizard' group immediately if he were offered the gig, whether they were successful or not.
He said: ''He was a mad Beach Boys fan.
''He would have left The Who at the drop of a hat to join the Beach Boys. Even at our height, when the Beach Boys were on their way down and The Who were at the top of the world, if the Beach Boys had asked him to drum for them, he would have gone.''
Roger - who with guitarist Pete Townshend are the only remaining members of the rock band, after the death of bassist John Entwistle in 2002 - admits they covered Beach Boys' 1965 song 'Barbara Ann' to keep him in the band.
He added: ''We used to do 'Barbara Ann' to keep him happy!''
'The Beach Boys With The Royal Philharmonic Orchestra' - produced by Don Reedman and Nick Patrick - is out now, and Mike, Bruce Johnston and Al Jardine will perform at Hampton Court Palace Festival on Friday (15.06.18) and Saturday (16.05.18).