Betty's 1930 debut, as a canine-featured singer in a restaurant where Bimbo is a frazzled waiter.

Public domain (US): Published 1930; all works published in the US before 1931 (and foreign works published before 1931) are public domain in the US (95-year term expired). Source: Internet Archive (https://archive.org/details/BettyBoopDizzyDishes1930).