Cynthia Lennon, John Lennon's...

...first wife and the mother of Julian Lennon, died at age 75.

Lennon's son, who looks and sounds eerily like his father, is probably best known for his song, "Too Late for Goodbyes," which peaked at number one on the US Adult Contemporary chart in 1985. Adult Contemporary? Ouch. Am I embarrassed* to admit that I find this tune catchy? A little. (Sue me.)

Julian Lennon, according to Wikipedia (my emphasis):

...inspired one of his father's most famous songs, "Lucy in the Sky with Diamonds," whose lyrics describe a picture the boy had drawn, a watercolor painting of his friend Lucy O'Donnell from nursery school surrounded by stars.

And you thought the song was about LSD.

Following his father's infidelity with Yoko Ono, Lennon's parents divorced when he was five. Paul McCartney wrote "Hey Jude" to console him over the divorce; originally called "Hey Jules," McCartney changed the name because he thought that "Jude" was an easier name to sing.

* It's not even a good lip-synch. And where was Jean "Toots" Thielemans on the harmonica?