From "Top Hat", the 1933 Irving Berlin musical.
I loved that movie. I first saw it in college attending a Film Lecture class (2 hour credit but filled a requirement).
Our grad student “teacher” was showing us the editing and directing that, up to that point, hadn’t been done much. There is a seamless scene in the classic “bait and switch” mode that was done with multiple cameras with one or two takes.
I’ll always love Ginger’s response to a question on who was the better dancer. She, with class as usual, said she didn’t know but she did the same moves as Fred but only backwards and in heels! (total paraphrase)