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The Ten Coolest Celebrities Appearing At This Weekend's Dallas Sci-Fi Expo.

Since 1994, the Dallas Comic-Con's Sci-Fi Expo has been helping geeks shout their their geekdom from the rooftops, and this year's affair, set at the Irving Convention Center this weekend, is no different in that regard. In fact, one could argue, it's even better than ever.

Sure, per usual, this year's convention features its fair share of comic book icons — Adam Hughes (Wonder Woman and Before Watchmen illustrator) and George Perez (1970s and '90s Avengers illustrator) — but where this Sunday and Saturday event really shines is on the celebrity front. Cosplay diversions aside, there are indeed some pretty cool film and television stars to catch this year. Actors from Battlestar Galactica, The Walking Dead, Serenity, Tron Lord of The Rings, Back to the Future and even Hercules himself more will be among the stars on hand.

Here, we go over the 10 most worthy of dropping some dough on to meet (after an entry ticket purchase, no less, and those start at $20) — because, cool or not, that's unfortunately just kind of how these things work.

Celebrity: Christopher Lloyd.
Why He's Here: Because he played Doc Brown in the Back to the Future franchise.
Why You Should Care: He's Christopher Lloyd, dammit! Didn't like him in Back to the Future? You're crazy, but maybe you liked him in Taxi or as Uncle Fester in the Addams Family movies or as the bad guy in Who Framed Roger Rabbit? or as the freaking angel in Angels in the Outfield.

Celebrity: Edward James Olmos.
Why He's Here: Because he played Admiral (spoiler alert!) Adama on the excellent Battlestar Galactica reboot.
Why You Should Care: In 1988, he became the first American-born Latino to be nominated for a Best Actor award at the Oscars, thanks to his role as an English teacher in Dangerous Minds a principal in Lean on Me a math teacher Stand and Deliver. Also, he played Selena's dad in Selena.

Celebrity: Kevin Sorbo.
Why He's Here: Because he's Hercules.
Why You Should Care: Because he is Hercules. Also, he played Ryan's estranged father on The O.C.

Celebrity: Andrew McCarthy.
Why He's Here: No clue, really.
Why You Should Care: Honestly, McCarthy's appearance here makes next to no sense. But his run in the '80s in such amazing films as St. Elmo's Fire, Mannequin, Weekend at Bernie's, Pretty in Pink and Less Than Zero was pretty choice.

Celebrity: Lea Thompson.
Why He's Here: Because she played Marty McFly's mom, Lorraine, in Back to the Future.
Why You Should Care: You may also remember her as the object of Eric Stoltz' affection and Mary Stuart Masterson's ire in Some Kind of Wonderful or as the titular “Caroline” in Caroline in the City. Or, perhaps, you best remember her as Howard the Duck's love interest. Or as one of the two females in Red Dawn.

Celebrity: Billy Boyd.
Why He's Here: Because he played Pippin in the Lord of the Rings trilogy.
Why You Should Care: I dunno. He's probably the least interesting of the hobbits who got any play in that series. Still.

Celebrity: Morena Baccarin.
Why He's Here: Because she played Inara in Serenity and Firefly.
Why You Should Care: She also played the evil alien queen in the terrible ABC reboot of V a few weeks back, so maybe you can ask her what it was like to work with Scott Wolf of Party of Five and the very underrated White Squall.

Celebrity: Laurie Holden.
Why He's Here: Because she plays Andrea in The Walking Dead.
Why You Should Care: The Walking Dead is one of the top five shows on television right now and Holden's Andrea is carrying a whole plot line by herself this season. She's only appearing at the convention on Sunday, though. Coincidentally, that's the same day that Season 3 of the show starts back up on AMC. She's joined at this affair by Danai Gurira, who plays Michonne on the show, and who will be at the convention on both days.

Celebrity: Glenn Morshower.
Why He's Here: Because he's been in everything, dammit.
Why You Should Care: This Dallas-born character actor is one of Hollywood's consummate “that guy” types; you recognize his face and his work, but not his name. His most prominent role? Maybe his turn as Secret Service agent Aaron Pierce in 24? Perhaps his run as Landry's dad on Friday Night Lights? Tough to say. But you sure recognize his face, don't you?

Celebrity: James Tolkan.
Why He's Here: Because he put the “pal” in principal in Back to the Future and was also Maverick's ball-bustin' commander in Top Gun.
Why You Should Care: Because he uttered this great line from movie history. “Son, your ego is writing checks your body can't cash.”

For a full list of celebrity appearances at this year's event, check out the Sci-Fi Expo's website.