Without looking anything up, I'd guess it has to do with John either joining the band to complete the lineup or his first official gig in Queen?
It was John's first gig with Queen.
That's not quite correct now.
Then, as with most of your posts, it's probably worth correcting most biographies rather than picking your nose and gloating on an internet forum. :o)
(I only said that because I was picking my nose as I typed)
jim morrison died
british soldiers shot N/Ire protesters
voting age in USA lowered from 21 to 18
oh, and i was almost 9 yrs old