Indeed. The live action sing-along sequence is from one of the earliest Fleicher Studios cartoons to feature Betty Boop, and shows Ethel Merman singing
Sweetheart. These 'bouncing dot' singalong shorts began as a technological cutting edge sound experience in selected cinemas as early as 1926 (a different series). This one is from 1930.
It's interesting to note how far back this precursor to karaoke dates - as far back, in fact, as sound was technically feasible on film. Another cool thing is the pictogram-speak! Text-messaging short forms 60 yrs ahead of their time :)
Full version:
Sweetheart (1930).
Wiki:
https://en.wikipedia.org/wiki/Screen_Songs You're it, TheDudeLebowski.