 Astaire's first seduction of Rogers in "Isn't This a Lovely Day," falls foul of the mistaken-identity theme of the plot, so he makes a second attempt, encouraged by Broderick, in the number "Cheek to Cheek".As in "No Strings," the song emerges from Astaire's mid-sentence as he dances with the hesitant Rogers on a crowded floor.Berlin wrote the words and music to this enduring classic in one day, and, at 72 measures, it is the longest song he ever wrote.