Dawson Casting: Played straight with Jennifer Lawrence and Josh Hutcherson, who are in their early 20s and play 17-year-olds. Averted with Sam Clafin, who's close to Finnick's age. Zig-zagged with Jena Malone, who was in her late 20s playing a character in her early 20s.
Sam Claflin has seriously put on muscle for his role as Finnick.
Jennifer Lawrence, who had plain brown hair in the first movie, had her hair dyed black for Catching Fire, which is closer to Katniss' physical description in the books. Her skin also looks noticeably tanned in certain scenes, compared to the first film. note In the books, Katniss was Ambiguously Brown, and her being played by wholly Caucasian Jennifer Lawrence caused quite a few outcries of whitewashing.
Liam Hemsworth and Josh Hutcherson also both dyed their hair again for their roles.
Fake American: Brit Sam Claflin as Finnick, and also Aussie Liam Hemsworth as Gale.