Right now (and for the past several days) it has been "You'll Play Your Part", from the show
It has wormed its way into my ear so bad that I've been singing that catchy refrain at the end off and on all day, every day. I've been driving my family crazy with it, lol.
"Know that your tiiiiiiiiiime is coming soon! As the sun rises so does the moooon! As love finds a plllace in ev-er-y heaaart, you are a princess, you'll plaaaaaaay your part~" Just like that.