Zac Efron and Amanda Seyfried Join Scooby-Doo Voice Cast

It looks like Mystery Inc. is about to get their head in the game with a mean girl. Deadline reports that Zac Efron and Amanda Seyfried have signed on to the upcoming Scooby-Doo animated movie, playing Fred and Daphne, respectively. They join the previously cast Will Forte (Shaggy), Gina Rodriguez (Velma), Tracy Morgan (Captain Caveman), …