She’s gone from “Twilight” to “Charlie’s Angels,” but now she’s taking on her biggest role yet … and it looks like Kristen Stewart royally nails it.

The actress is in full Princess Diana mode in Germany this week on set of the upcoming film “Spencer” … rocking a vintage Lady Di look, with glasses and without.

Obviously, Kristen’s Adidas kicks are just for getting around on set and not what the Princess of Wales wore back then … at least we don’t think so.

As for the movie … the title is Diana’s maiden name — for the young’uns not in the know — and the plot revolves around a weekend she spends with the British Royal Family before deciding to divorce Prince Charles.