Heigl: 'Grey's schedule is cruel and mean'

Katherine Heigl has branded the schedule of Grey's Anatomy "cruel and mean" because it requires the cast to work very long hours.

The actress, who plays Dr Izzie Stevens in the medical drama, told The Late Show With David Letterman that she had endured a mammoth first day of filming for the upcoming season.

"Our first day back was Wednesday and I'm going to keep saying this because I hope it embarrasses them, it was a 17-hour day, which I think is cruel and mean," she said.

"It was actually kind of great to be back. All my friends are there and at this point, they’re sort of like family but it was a little weird because [T.R. Knight is] not there anymore."

The star added that she hopes Grey's will continue to be successful, saying: "We have another two years, I think, at least in the contract. Hopefully the show goes into ER time, which would be cool."

Heigl can next be seen opposite Gerard Butler in romantic comedy The Ugly Truth, which opens on August 7.