The former Arsenal defender has put pen-to-paper on a season long loan deal.
Speaking following his arrival Song said, “I’m very happy to be here and very happy to see the guys and the fans today and to start to do my job for West Ham United. I think this is very important for me to be coming back to London to West Ham United, which is a club with ambition to build a new stadium and become a big club. I am very excited to be part of this project.”