From ABC's official press release:

Derek, engagement ring in hand, searches for the perfect way to propose to Meredith, on ABC's Grey's Anatomy.

Guest starring Academy Award nominated actress Mary McDonnell (Passion Fish, Battlestar Galactica) as Dr. Dixon, Golden Globe-Nominated actress Melissa George (In Treatment, Alias) as Sadie, and Jessica Capshaw (The Practice) as Dr. Arizona Robbins.

Now that Derek has the engagement ring, he searches for the perfect way to propose to Meredith, as Lexie demands that Mark go public with their relationship, and Bailey, encouraged by her work on recent cases and by Dr. Dixon, considers a new direction for her medical career, on Grey's Anatomy, Thursday, Febraury 5 (9:00-10:02 pm, ET) on the ABC Television Network

Grey's Anatomy stars Ellen Pompeo as Meredith Grey, Patrick Dempsey as Derek Shepherd, Sandra Oh as Cristina Yang, Katherine Heigl as Isobel "Izzie" Stevens, Justin Chambers as Alex Karev, T.R. Knight as George O'Malley, Chandra Wilson as Miranda Bailey, James Pickens, Jr. as Richard Webber, Sara Ramirez as Callie Torres, Eric Dane as Mark Sloan, Chyler Leigh as Lexie Grey and Kevin McKidd as Owen Hunt.


Source: ABC
(Image courtesy of ABC)