The single-player add-on pack will be available on PS3 and PS4 the following day in the UK, publisher Ubisoft has confirmed.
Freedom Cry is a nine mission self-contained story starring Adewale, who plays protagonist Edward Kenway's first mate in the main game.
According to the official blurb: "Born a slave, Adewale found freedom as a pirate aboard the Jackdaw as Captain Edward Kenway's second-in-command. Fifteen years later, Adewale has become a trained assassin and finds himself shipwrecked in Saint-Domingue with no weapon nor crew, starting a new adventure of his own."
"The fact that ACIV is so good was by no means a foregone conclusion," we wrote in our Assassin's Creed 4 review in late October. "There was a sense that, as the dust settled after ACIII, Ubisoft had missed a beat. Brows rightly furrowed as commentators pondered whether the series had already overshot its zenith.
"Much like the first Assassin's Creed, Black Flag isn't perfect. But the treasure trove of memorable experiences on offer here put all but the very best open worlds to shame."