The next time you call your friend who supports efforts to eradicate autism, you just might hear the voice of Cher. Or Mark Hamill (Luke Skywalker). Or Jack Black.

For only $299, any one of these actors will record your voice mail message, or will record a direct message to a friend or loved one as part of the campaign Sound Off for Autism Speaks. If it's less than 20 seconds long or 250 characters, they will probably say just about anything you want, and the money raised will go to AutismSpeaks.org

Other celebrities taking part are Adam West (Batman), Jim Parsons (Big Bang Theory), Vin Scully (voice of the LA Dodgers) and Bryan Cranston (Breaking Bad), but both of the last two are already 'sold out'.