We're not sure how long she'll be sticking around - although we do know she will appear in this week's "Don't Stand So Close to Me" - we thought you might like to know a little about this talented actress.
Growing up in New York, in the shadow of show business as the daughter of powerful publicist Lois Smith, Brooke's big break came as Catherine Martin, the abducted young girl in The Silence of the Lambs.
Other key roles included Sonya in Louis Malle's Vanya on 42nd Street, as well as Dawn in Daniel Minahan's Series 7: The Contenders. Her TV credits include Law & Order, Six Feet Under, Heist and Crossing Jordan. Smith, 39, has more than three dozen movie and TV credits to her name.
Whether she is humming a Tom Petty tune, like her character does in Silence of the Lambs, or showing a different side of pregnancy as she did in Series 7, Smith is known for giving brooding, intense performances - as Grey's Anatomy fans have seen from the four episodes she's appeared in.
In addition to acting, she also enjoys filmmaking. She has directed a short film and a feature length documentary, and published interviews with actors Steve Buscemi, Ed Harris and Fred Ward (who also guest starred on Grey's Anatomy this year as Denny, Sr.), among others.
A medical school rival and frequent adversary (but nonetheless, respected colleague) of Preston Burke, Dr. Hahn adds yet another dynamic presence to Seattle Grace Hospital. Hopefully we get to see more of her.