I recently watched the "Get Back" documentary series about the Beatles. Not being a musician, there were long parts (especially during the first episode) that were pretty tedious to me. But my favorite part came during the third episode when Paul McCartney's soon-to-be wife Linda came to the studio and brought her daughter Heather. After Paul and Linda married, he formally adopted Heather.
It's clear from the footage that Heather was a self-confident, precocious six year old. She played and interacted amusingly with all of the band members.
But what stood out to me was the bond between Paul and Heather. A few still shots from that day tell the story.
When the Beatles broke up shortly after these sessions, Paul credits Linda with being the one who helped pull him out of depression. His song "Maybe I'm Amazed" was his tribute to her. But based on the more recently remastered video of that song, it is clear that Heather played a pretty important role as well.