"There were record-breaking temperatures last summer in London and because that phenomenon was so remarkable and unusual, England is ill-equipped to cope with such an event and so there was no air conditioning. I was wearing layers of wool petticoats and things and a very constricting corset," Danes told reporters in New York recently.
She recalled a scene in which she "erupts in a fit of anger" as particularly difficult to shoot in the heat.
"I could barely focus," she revealed with a laugh. "I was just so overwhelmed by the heat and I was just praying there would be a (warning) at the bottom of the screen, saying, 'Please excuse Claire's horrible acting because the conditions were unreasonable.'"
"Stage Beauty," co-starring Danes' real-life beau Billy Crudup, is in theaters now.