The appointments follow a review overseen by AAR of a consumer brief covering its entertainment offerings LoveFilm, Kindle and Amazon MP3, and separate briefs covering retail and product placement.
It is undersood that Bite Communications has been appointed to the entertainment brief, while Unity and Ideas Network have also been brought on board.
The Red Consultancy, which handled work for Amazon focusing on the Kindle tablet, is no longer working with the company.
Ideas Network and Bite declined to comment, while Unity and Amazon had not yet responded to a request for comment.