The song was written by Irving Berlin for one of his favourite performers. It's called: You're Just In Love

(I WONDER WHY) YOU'RE JUST IN LOVE IrvingBerlin from Call Me Madam [Kenneth:] I hear singing and there's no one there I smell blossoms and the trees are bare All day long I seem to walk on air I wonder why I wonder why I keep tossing in my sleep at night And what's more I've lost my appetite Stars that used to twinkle in the skies Are twinkling in my eyes I wonder why   [Sally:] You don't need analyzing It is not so surprising That you feel very strange but nice Your heart goes pitter patter I know just what's the matter Because I've been there once or twice Put your head on my shoulder You need someone who's older A rubdown with a velvet glove There is nothing you can take To relieve that pleasant ache You're not sick You're just in love