It looks as if we may have confirmation that Anne will be in the upcoming movie One Day.  The Associated Press just released this short statement:

The star of Ella Enchanted and The Princess Diaries will appear in the film adaptation of David Nicholls’ popular novel One Day, about a working-class woman’s romance with a charming rich man, played by Jim Sturgess.

The movie begins filming this summer. It will be directed by Lone Scherfig, an Oscar nominee for An Education.

The project was announced Tuesday by Focus Features and Random House Films, which have a partnership.

I also found an article on upcoming films at hollywoodnews.com and they gave a little bit of info on the plot.

…which will open in the third quarter of 2011. It stars Academy Award nominee Anne Hathaway in a film directed by An Education helmer Lone Scherfig. David Nicholls has completed adapting the screenplay, based on his acclaimed novel of the same name. Emma (Ms. Hathaway) and Dexter meet on the night of their graduation – July 15th, 1988. She is a working-class girl of principle and ambition who dreams of making the world a better place. He is a wealthy charmer who dreams that the world will be his playground. But where will they be on this day next year, and the year after that? Over 20 years, we check in on Emma and Dexter every July 15th, and watch as their friendship ebbs and flows with the passing of the years.