It's Halloween and Lexie Grey is certainly looking the part... of an Amish girl, or Raggedy Ann doll. Not sure which!

What happens in the elevator, doesn't stay in the elevator as Alex blows George's cover as a repeater. Jerk.

Lexie Grey and her estranged older sister Meredith Grey talk about some things. This family drama promises to take over their lives in and outside the hospital in Season Four.

Lexie Grey is a cutie... although it's unclear whether she will become romantically involved with anyone at the hospital. Who, if anyone, will it be?

The biggest addition to the cast of Grey's Anatomy in Season Four is the cute Chyler Leigh, who plays Lexie Grey, sister of Meredith Grey. We're looking forward to seeing where this character is headed.

Lexie Grey (Chyler Leigh) is a new intern at Seattle Grace. So are those other peeps, but we're most concerned with the girl threatening to break up our MerDer love.

Eh, that couple nickname just doesn't work. Neither does the chemistry between these characters. Right, fans?

Lexie Grey. Meredith Grey. Face-off. What will transpire as the two sisters must work together at Seattle Grace?

Lexie Grey flashes a smile at Seattle Grace. Will the interns grow to love or hate this new cutie?

The Season Four cast of Grey's Anatomy: Starring the lovely Ellen Pompeo (Meredith Grey), Patrick Dempsey (Derek Shepherd), Sandra Oh (Cristina Yang), Katherine Heigl (Izzie Stevens), T.R. Knight (George O’Malley), Justin Chambers (Alex Karev), Chandra Wilson (Miranda Bailey), James Pickens, Jr. (Richard Webber), Sara Ramirez (Callie Torres), Eric Dane (Mark Sloan) and Chyler Leigh (Lexie Grey).