The woman who was said to have inspired the Beatles song Lucy in the Sky with Diamonds has died at the age of 46 of the immune system disease Lupus.
It was rumoured the song featured on the Sergeant Pepper's Lonely Hearts Club Band album was about the drug LSD.
But Lennon insisted it was inspired by a drawing by his son Julian of Lucy, a classmate while they were at a nursery in Weybridge, Surrey in 1966.
The St Thomas Lupus Trust said Lucy Vodden, of Surbiton, died on Tuesday.
The trust, which had been supporting Mrs Vodden and her husband Ross during her illness, announced her death.
Angie Davidson, trust campaign director, said: "Everyone at the Louise Coote Lupus Unit was dreadfully shocked by the death of Lucy. She was a great supporter of ours and a real fighter.
"It's so sad that she has finally lost the battle she fought so bravely for so long."
The trust said Julian Lennon and his mother Cynthia were "shocked and saddened" by Mrs Vodden's death.
The former classmates had resumed their friendship in recent months when Lennon heard that Lucy had become ill.
When Lucy in the Sky with Diamonds was released in 1967 it was banned by the BBC for its supposed drug references.
Julian said he took his picture of Lucy home and showed it to his father, explaining: "It's Lucy in the sky with diamonds."