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"Grey's Anatomy's" Neve Campbell

Prepare to meet Derek's mysterious sister, Liz "Lizzie" Shepherd on ABC's Grey's Anatomy.

Neve Campbellwill reunite with her Scream 3 co-star Patrick Dempsey as Derek's previously unnamed fourth sister in a pair of December episodes of the ABC medical drama and The Hollywood Reporterhas a first-look at her character.

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Lizzie first arrives in the closing moments of the Dec. 6 hour, titled "Love Turns You Upside Down," when Meredith (Ellen Pompeo) asks intern Heather (Tina Majorino) to go above and beyond to help fix her husband's hand. Campbell will return the following week for the episode titled "Run Baby Run."

Details about the nature of the Shepard siblings' relationship are being kept under wraps, but Lizzie -- who appears to be married judging by the ring on her finger in the image above -- will return Dec. 13 for the "Run Baby Run" hour.

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Of Derek's four sisters, Campbell's Lizzie marks the third of four Shepherd sisters on Grey's Anatomy. Caterina Scorsoneplays Amelia Shepherd on Grey's spinoffPrivate Practiceand Embeth Davitzpreviously appeared as his sister, Nancy. Psychiatrist Kathleen Shepherd has been mentioned but has yet to appear on the Shonda Rhimes series.

Check out the first-look photos (above, and below with Majorino) and hit the comments with your thoughts on how you think the Shepherd siblings will get along. Grey's Anatomy airs Thursdays at 9 p.m. on ABC.

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'Grey's Anatomy' First Look: Neve Campbell as Derek's Mysterious Sister (Photos)