Ten-year-old actress Abigail Breslin, who can currently be seen in the critically-hailed, independent feature Little Miss Sunshine, will guest star in an upcoming episode of Grey's Anatomy.

The episode, entitled "Sometimes a Fantasy," has not yet been given an airdate. In its first three episodes of the news season, Grey's Anatomy will welcome guest stars including Breslin, the legendary Diahann Carroll and actor Chris O'Donnell (returning in his role as veterinarian Dr. Finn Dandridge).

Acclaimed by audiences and critics alike and the recipient of multiple Emmy Award nominations, "Grey's Anatomy" returns to the ABC Television Network for a third season. The interns have learned a lot since their first year at Seattle Grace Hospital - not only about surgery, but about themselves and one another. The third season will premiere on THURSDAY, SEPTEMBER 21 (9:00 p.m., ET).

There's Izzie, who has decided there may be more in her life than medicine after falling in love with Denny, a patient whose life she fought to save... and lost. Now that she's quit the intern program, Izzie will see what a future without the hospital has in store.

Best friend George has had his own ups and downs in love. Having his dreams of a relationship with Meredith crushed after a demoralizing one-night stand with her, George found love in the unlikeliest of people - the tough, unique Orthopedic Surgeon Dr. Callie Torres. Callie sees and loves all of the qualities that make George who he is, and in return George likes her being the kind of woman who will stand up for him and their relationship.

Alex Karev may be the surgical intern all of the other interns love to hate, but the cocky and often callous Alex has been there for his fellow students when it matters.

Focused and ambitious intern Cristina Yang has wanted one thing her whole life -- to become a talented and successful surgeon. Cristina, who once lacked all bedside manner, is now allowing her allegiances to friends and her emotions to seep into her work. One of her greatest emotional challenges is yet to come, as she must become a source of support and assistance to her boyfriend, Cardiothoracic Surgeon Dr. Preston Burke; highly respected among his fellow surgeons, Burke must deal with a potentially career-ending tremor in his hand, the result of a near-fatal shooting accident at the hospital.

And then there's Meredith Grey. After Meredith and Derek "McDreamy" Shepherd's ever-present sexual tension culminated in a moment of passion, they have to face the consequences. Meredith was just beginning to fall for the attractive and available veterinarian, Finn. And there's the matter of Derek's wife, Addison. A neonatal surgeon at the hospital, Addison is a woman trying to put her own indiscretions in the past and to save her marriage.

The interns, as always, will be under the guidance of "The Nazi," Dr. Miranda Bailey, who both terrorizes and nurtures them. Bailey maintains a tough exterior, but with these interns, it's hard not to display her softer side from time to time. Supervising the whole operation is The Chief, Dr. Richard Webber. His past indiscretions with Meredith's mother, Ellis, have been exposed and he must now deal with the consequences to his family and professional life.

The doctors of Grey's Anatomy choose to live life to its fullest amidst the daily life-and-death stakes of their jobs. It's the drama and intensity of medical training mixed with the funny, sexy, painful lives of interns who are discovering that neither medicine nor relationships can be defined in black and white. Real life only comes in shades of grey.

Grey's Anatomy stars Ellen Pompeo as Meredith Grey, Patrick Dempsey as Derek Shepherd, James Pickens, Jr. as Richard Webber, T.R. Knight as George O'Malley, Sandra Oh as Cristina Yang, Katherine Heigl as Isobel "Izzie" Stevens, Chandra Wilson as Miranda Bailey, Isaiah Washington as Preston Burke, Justin Chambers as Alex Karev, Kate Walsh as Addison Shepherd and Sara Ramirez as Dr. Callie Torres.