The cover of the Nov. 23, 1970 issue of TIME features a whimsical-looking Big Bird, his head crowned by a halo of bright lights and his mouth agape, perhaps mid-song. The story lauds the then one-year-old program as “not only the best children’s show in TV history,” but “one of the best parents’ shows as well.” And the show was revolutionary on both fronts. Not only was it was the first show to incorporate theories of early childhood development into its programming, but it was also one of the first to offer something for the grown-ups, not least of all its celebrity appearances.

Sesame Street’s use of celebrity cameos and pop culture references to appeal to adults was strategic. Creator Joan Ganz Cooney hoped parents would adopt the educational values the show promoted. And parents, after all, wielded the power when it came to the remote control. They’d be more likely, of course, to tune into a show that didn’t drive them from the room, seeking cover (see: Barney and Friends, two decades later).

Since debuting 45 years ago today, Sesame Street has featured hundreds of actors, musicians, politicians and athletes helping children with their ABCs and their 123s, their vocabulary and their understanding of human emotions. Here are a few of the funniest, strangest and most heartwarming moments shared between the puppets and their celebrity friends.

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