I have an ear worm stuck in my head, but it is only a phrase.
It definitely is a slow ballad sung by a female (it might be a duet), and the phrase (which is the beginning of the first verse) goes something like this (not true to the pitch, only true to the intervals):
I'm very confident in the first part and not so sure if the green is just my imagined continuation of the phrase. It feels like it is somewhere from a musical (Disney movie maybe?) but I have no idea.
I've had this stuck in my head for a few days now, so I decided to give it a shot and ask here. Sorry for the lack of further information, it'll be nothing less than a miracle if someone recognises this.
Edit to add: Here are the harmonies (I - IV - V) and how I think they were arranged: