KEWLopolis is a three-hour children's programming block that began on CBS on September 15, 2007 replacing the KOL Secret Slumber Party which premiered on September 16, 2006 which in turn replaced Nick Jr. on CBS (later "Nick on CBS"), which was jointly produced by Viacom and Nickelodeon before CBS and Viacom became two separate companies. All programming in this block is in compliance with Federal "E/I" requirements -- as mandated by the Federal Communications Commission. The block is programmed by DiC Entertainment in conjunction with American Greetings (the former also programmed the previous Secret Slumber Party block).
After the announcement of the CBS/DIC partnership, the latter announced programming block was originally going to be called CBS's Secret Saturday Morning Slumber Party (or CBS’s Saturday Morning Secret Slumber Party), but was later renamed KOL Secret Slumber Party on CBS after DiC, who produced all of the children's programming for the block, partnered with KOL, the children's area of AOL, which co-produced programming with DiC. AOL managed the programming block's website, and produced public service announcements which aired both on television and online. This alliance was what led to the name change for this block, and also because some of the programs were airing on Sundays (depending on the market).
In mid-2007, KOL withdrew sponsorship of the block. Afterwards, CBS and DIC announced a new partnership with American Greetings Corporation to produce the new KEWLopolis programming block.