Carl's Jr. is launching the product with a new commercial titled "Cow Shake," featuring a large Holstein cow being "shaken" in rhythm to the music of "Get Busy," the hit song by Jamaican reggae star Sean Paul. As Paul sings "shake that thing," a young man attempts to move the rigid black-and-white bovine, whose udder vibrates back and forth with the music. The pay-off line is "Milk ... Shakes." The ad is currently airing in local markets and will also be viewable on www.carlsjr.com.