From the press release:
The film portrays a period in the life of American Actress Grace Kelly (played by Nicole Kidman) who became Princess Grace of Monaco when she married Prince Rainier III (Tim Roth) in 1956, in what was dubbed “the marriage of the century”. An Oscar winner, she was already a huge film star, having worked with the very greatest (John Ford, Alfred Hitchcock, Fred Zinnemann) and acclaimed the world over. Six years later, amid occasional difficulties in fulfilling her role, she was invited back to Hollywood by Alfred Hitchcock, to play in his new film Marnie. At the time, France was threatening to tax and even annex Monaco, the tiny Principality whose monarch Kelly had become. Was she still an actress? Was she really Princess of Monaco?