Welcome back to the 1st annual Tournament of TV Fanatic: ABC edition!

It's time for you, TV Fanatics, to choose your favorite ABC star! We began with 16 fan favorites for this showdown. The concept is easy: Pick your favorite of the two pairs in each poll. That's it!

Semifinal #1 featured Patrick Dempsey and Stana Katic. Today it's Grey's Anatomy and Castle again, as Ellen Pompeo battles Nathan Fillion. BTW ... you gotta see this Castle season premiere clip!

Then cast your vote below. The finalists will be revealed Monday!

And the Winner is?

Nathan Fillion

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Vote for Nathan

Ellen Pompeo

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Vote for Ellen

Nathan Fillion vs. Ellen Pompeo: Which ABC star do you love the most? Vote now in this semifinal round matchup of the Tournament of TV Fanatic: ABC Edition! View Poll »

We will post polls of these respective ABC matchups daily, and then after each round, update the bracket as some stars advance, while others are eliminated, until the winner is crowned. Make sense?

It's easy, fun and decided by YOU! Here's the updated Tournament of TVF ABC field:

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.