All the talk in the world of adult animation over the past week or so has been about Family Guy. The internet is still buzzing after its writers decided to kill off a permanent member of the Griffin family - Brian - a plot which sent fans reeling. Petitions were launched, Twitter went into meltdown and fan theories were hatched, and while one Seth MacFarlane-created show continues to dominate conversation, another quietly trundles through its tenth series. American Dad! is currently into its final run (on the Fox network, don't worry) before making the move onto TBS for its upcoming season 11, and there's even talk of a potential film, which speculation suggests is to be set on Roger's home planet. Meanwhile, numerous special guest stars have recently been confirmed to star in the last ever series of American Dad! on the Fox network, including Zooey Deschanel (New Girl), Olivia Wilde (The O.C), Alison Brie (Mad Men) and American singer Mariah Carey, to name but a few. Down the years, there have been even more world-famous guest stars on the show, and here, to celebrate American Dad's imminent move to TBS, we take a look at the animation's 10 Greatest Guest Stars so far.