Nathan Fillion

Many Castle fans already view Nathan Fillion as a Greek god. And last summer during his hiatus, Fillion traveled to Vancouver to play Zeus’s son Hermes in the sequel Percy Jackson: Sea of Monsters (in theaters August 16). "I’m a god, father to one of the young demigods [half-blood Luke]," says Fillion. "I’m not allowed contact with humans as a god, so I dress as a UPS guy." Hermes, as you may recall, is the messenger of the gods.

In one scene, Hermes dons a suit and takes a group of child demigods on a long tour of his colossal parcel-sorting hub. "The three young actors restored my faith in humanity of what Los Angeles actors can be like," Fillion says. "They were having fun — supercool, prepared and professional. A very comfortable, great place to be!"