The deal was confirmed in Electronic Arts' third quarter financials, given to investors today. The game will be released at the end of the year.
Until now, Pandemic had chosen to reveal the game to the press and the rest of the industry itself without any publisher support.
LucasArts published the first Mercenaries game, but Pandemic kept the IP rights for the title, a negotiation almost unheard of for a big-budget console title handled by a large publisher. But perhaps ironically it was EA's involvement in the series in the first place that led to its creation: Pandemic originally started work on an previous gen update of 16-bit franchise Desert Strike, and while the game was ultimatley abandoned it was that project which in turn led to the creation of the Mercenaries series.
Electronic Arts' Partners publishing division will distribute the new game - the label also looks after the publisher's publishing relationship with Valve and other third-party studios.
The studio is one half of the Pandemic/Bioware company, a holding company that owns both of the two large North American independent studios and was funded by investment group Elevation Partners for $300m. The CEO of the holding company is Elevation MD, and former EA president and COO, John Riccitiello.