The 64th and final episode of the Fullmetal Alchemist: Brotherhood television anime series ended in Japan on Sunday with an announcement that production on a theatrical version has been green-lit. The 64th television episode matched the ending from Hiromu Arakawa's original manga.
Source: Temple Knights via Anime News Network
This is the second time Fullmetal Alchemist had a film treatment. The first one was with Fullmetal Alchemist: The Conqueror of Shamballa which is tied directly on the first series' last episode.