By Kate Ward
Updated March 23, 2010 at 03:53 PM EDT

People reports that Robert Downey Jr. and Katy Perry are two of many stars poised to appear at Nickelodeon’s 23rd annual Kids’ Choice Awards. Others who have RSVP’d yes for the event: Tina Fey, Steve Carell, Chris Rock, Jackie Chan, Jonah Hill, Queen Latifah, David Spade, Lea Michele, Dev Patel, Miranda Cosgrove and Shaun White. Apolo Anton Ohno will also be catapulted into green slime during the show. The awards, hosted by Kevin James, take place this Saturday.