The 'Harry Potter' star signs for a new film.

EMMA WATSON is taking over the role of Betsy Balcombe in 'Napoleon and Betsy' recently vacated by SCARLETT JOHANSSON, according to the Hollywood Reporter. Johansson opted out of the role when the part skewed younger than originally considered.

Balcombe was a young noblewoman who fell in love with the Napoleon when they were both confined on St. Helena, a British Isle.

Johansson will continue on in her role as a producer on the film, along with ALEXANDRA MILCHAN, MELANIE SLOAN and GILLES ARONDEAU.

Watson, who is best known as Hermione Granger in the 'Harry Potter' franchise, hopes to sandwich 'Napoleon and Betsy' between her commitments to 'Harry Potter and the Half-Blood Prince' and 'Harry Potter and the Deathly Hallows.'