Katherine Heigl gave David Letterman the “Ugly Truth” last night. While promoting her new movie on the “Late Show,” Heigl revealed that her first day back at “Grey’s Anatomy”—where filming stretched to 17 hours—was “cruel and mean.”

Last time we saw Heigl’s character, we were left wondering whether Izzie Stevens would survive brain surgery. Heigl hinted to Letterman that she’s still around this season, either as a miraculous survivor or a ghost. But I’m thinking what the writers decide for Izzie lies more in what comes out of Katherine’s mouth than the hours she works. Heigl backed up her labor complaint saying she hopes the “Grey’s” producers will be embarrassed now that everyone knows they are forcing actors to work such long days. But if Heigl keeps up her trash talking, I’m sure Izzie Stevens will “take a turn for the worse.” And Heigl’s workday will be much less taxing. Even non-existent. [MSNBC]

As a warning to Katherine, here’s a few other celebs who’s real-life beefs on set got them killed on-screen.