What actors and actresses appeared in The Darkest Hour - 1923?

There seems to be a misunderstanding. There is no movie titled "The Darkest Hour" from 1923.

The film "The Darkest Hour" that you might be thinking of was released in 2017 and stars Gary Oldman, Kristin Scott Thomas, Lily James, and Ben Mendelsohn.

It's possible you're thinking of a different film altogether. Could you please clarify the title or year of the film you're interested in?