After Patrick Dempsey's Dr. Derek Shepherd was killed off in the 11th season of "Grey's Anatomy," rumors surfaced that some of the past characters of the show would return to fill the vacant spot. One of the most prevalent speculations was the return of Dr. Izzie Stevens, played by Katherine Heigl. 

Past characters like Izzie, according to speculations, could comfort Derek's widow Dr. Meredith Grey (Ellen Pompeo) in the show's 12th season. However, Heigl quickly shot down the speculations, saying that it is not happening. The actress also told ET that she was devastated when she learned about Derek's death.

"I just can't imagine the show without McDreamy," Heigl stated regarding the death of Dempsey's iconic character. "It's just so hard to picture." 

Izzie was one of the original characters of "Grey's Anatomy" when it premiered in 2005 but left after the 12th episode of season 6 that aired in 2010. While Derek's exit from the show was very clear — he died due to a fatal car crash —Izzie's fate after leaving Seattle is still unknown. This is probably the reason why fans would like to see the actress give closure to her character. 

But while the 36-year-old actress already declared that she will not appear in the long-running medical drama in the near future, she still feels grateful for having been a part of the series.

"It changed the course of my life and my career, and I couldn't be more grateful," Heigl stated. She also said that she wants to see more of the show, saying, "I just hope it goes for as long as they all want it to."

Meanwhile, it was earlier reported that a new doctor will join the staff of Grey Sloane Memorial Hospital, and it will be portrayed by "Secrets & Lies" actor Martin Henderson.

"Grey's Anatomy" season 12 is expected to premiere in ABC beginning September.