Mini biography of Syd Barret;
https://en.wikipedia.org/wiki/Syd_Barrett
Barrett visited the members of Pink Floyd in 1975 during the recording sessions for their ninth album, Wish You Were Here. He attended the Abbey Road session unannounced, and watched the band working on the final mix of "Shine On You Crazy Diamond" — a song about him. By that time, Barrett, then 29, had become overweight and had shaved off all of his hair (including his eyebrows), and his former bandmates did not initially recognize him. Barrett spent part of the session brushing his teeth. Waters asked him what he thought of the song and he said that it "sounds a bit old". He briefly attended the reception for Gilmour's wedding to Ginger that immediately followed the recording sessions but left early without exchanging goodbyes with the newlyweds.
Apart from a brief encounter between Waters and Barrett in Harrods a couple of years later (Barrett ran outside when he saw Waters, dropping his bags full of sweets),this was the last time any member of Pink Floyd saw him.
Barrett visiting Abbey Road Studios on 5 June 1975