A majority of workers at videogame publisher Activision Blizzard Inc's recently acquired studio Proletariat said on Tuesday that they are forming a union with the Communications Workers of America.

The move would make the Boston-based studio, the third Activision Blizzard studio to seek unionization.

The 57 workers in the Proletariat unit – that include animators, designers, engineers, producers and quality assurance workers – said they have filed for a union representation election with the National Labor Relations Board.

Earlier in July, Activision said that it had Proletariat to expand the development pipeline of its online role-playing game "World of Warcraft". Activision did not immediately respond to a Reuters request for comment. Workers who test games at Activision's unit Blizzard Albany have voted to form a union months after the company began negotiating with employees at its Wisconsin unit, the first in the company to unionize.

Xbox maker Microsoft Corp agreed to buy the Call of Duty maker for $69 billion, a deal that has faced antitrust backlash from the Federal Trade Commission (FTC), the European Union and the United Kingdom's Competition and Markets Authority.

(Reporting by Tiyashi Datta and Akash Sriram in Bengaluru; Editing by Shailesh Kuber)