The Clear Channel AC station had scheduled a holiday kickoff party for Disneyland tonight, but the Wednesday afternoon studio visit by artist Michael Buble to the Brian Simmons show featured a request from the singer - go all-Christmas right now. Buble convinced Simmons to find the Christmas tunes (no doubt in a pre-arranged bit) and KOST is now all-Christmas through December 25. The station says last year's holiday format made the cume (total audience) grow past six million Los Angelenos. Track the all-Christmas stations in chronological order (with help from Nielsen BDSRadio) here. The Los Angeles Board of Radio-Info.com caught the Michael Buble visit and changeover, and the thread is here.