Yes... according to him, it was one of his very demanding children who told him something like, "Bilbo's front door was blue, and now you've said it's red," or something like that. So he started writing down the story so he wouldn't contradict himself, hahaha. Afterward, the writings began circulating among friends until they reached a woman who was an editor, and she convinced him to finish the work.

The video I posted shows how he started writing the story.

EDIT:

I bought this book here at home a while ago, to introduce my child to Tolkien's work.