The 39-year-old will star in the upcoming period drama, which is written and directed by Werner Herzog, reports femalefirst.co.uk.
In the movie, Watts will play Gertrude Bell, a pioneering explorer, writer, archeologist and attache for the British Empire, who is credited with helping to administer the modern Iraqi state at the beginning of the 20th century.
Pattinson will portray her collaborator T.E. Lawrence and Law's role is not yet specified, but it is believed he could be playing Charles Doughty-Wylie, with whom Gertrude had a two-year affair.
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