Katy Perry didn’t make the cut on Sesame Street.

The video of the pop star singing a remixed version of Hot N Cold with Elmo was deemed inappropriate for preschoolers.

Maybe she should have worn a slightly less revealing dress.

Over the years lots of celebrities have made the cut–sporting conservative dress. As Sesame Workshop said in a statement today: “Sesame Street has always been written on two levels, for the child and adult. We use parodies and celebrity segments to interest adults in the show because we know that a child learns best when co-viewing with a parent or care-giver.”

Here’s a roundup of the 20 best celebrity appearances on Sesame Street. Some of these stars have reputations far more questionable than Perry’s but they disguised their vices with conservative dress.

Feel free to share your favorite Sesame Street celeb cameos in the comments.

20) Elmo interviews Jenny McCarthy–and they sing “Twinkle Twinkle Little Star” together

19) Jack Black defines Octagon

18) REM performs “Furry Happy Monsters” with a bunch of bouncing monsters





17) Ben Stiller sings about friends and neighbors

16) Julia Roberts with Elmo

15) Marisa Tomei updates the classic tale “The Frog Prince” with a heavy New York accent

14) CNN correspondent Anderson Cooper on his toughest assignment yet

13) Norah Jones sings “Don’t Know Y”

12) Natalie Portman And Elmo Are Princess & Eleph

11) Yo Yo Ma jams with some honkers

10) Johnny Cash gets grumpy with Oscar and sings “Nasty Dan”

9) Ray Charles, Tony Bennett, Susan Sarandon, Ellen DeGeneres, and more sing the alphabet

8) Andrea Bocelli’s Lullabye To Elmo

7) Little Richard sings “Rubber Duckie”

6) Richard Pryor offers a comical take on the alphabet

5) Paul Simon sings “Me & Julio”

4) Feist sings the ubiquitous 1-2-3-4 song

3) Billy Joel And Marlee Matlin Sing Just The Way You Are

2) Tina Fey sings a sea shanty encouraging kids to read

1) Lily Tomlin on Edith Ann’s sandwich

Which celebrity appearances are we missing? Which ones are your favorites?