Lavender's Blue
"Lavender's Blue" is an English folksong and reflects on becoming "king and queen"--when lavender is blue and, since it is purple, is similar to saying "when pigs fly," suggesting that it is very unlikely! Common "folk" probably enjoyed reflecting on that possibility though, when they could "call up [their] men... set them to work" (verse 2) all "whilst you and I....keep ourselves warm" in comfort and luxury (verse 3). The enjoyable, nonsense "diddle, diddle" and tune make it a fun song to sing with children.
The Live-Action Disney Cinderella of 2015 showed Lily James singing the song as she worked.