Old black and white movie with Romeo and Juliet stop motion puppets

I need help identifying a strange movie I saw many years ago; the scene goes as follows: a girl and guy singer are singing live in a studio while 'stop motion' puppets act out 'Romeo and Juliet'. The 'Juliet' puppet is a cat, and the 'Romeo' one is a fox (I think). While the girl is singing, these men in the studio keep taunting her (i.e. scaring her, trying to make her laugh, etc.) I would date this movie as possibly 1940s, and it used to air on AMC many years ago. If someone could please help me identify what this is I would appreciate it.

Thanks!