Isobel Katherine Stevens, M.D. is a fictional character from the medical drama television series Grey's Anatomy, which airs on the American Broadcasting Company (ABC) in the United States. The character was created by series producer Shonda Rhimes, and was portrayed by actress Katherine Heigl from 2005 to 2010. Introduced as a surgical intern at the fictional Seattle Grace Hospital, Izzie worked her way up to resident level, while her relationships with her colleagues Meredith Grey (Ellen Pompeo), Cristina Yang (Sandra Oh), Alex Karev (Justin Chambers) and George O'Malley (T. R. Knight) formed a focal point of the series.