Lendlease will now work with Peabody in a corporate joint venture to masterplan and deliver the mammoth scheme over the next 30 years.
Lendlease won the deal after beating a rival bid from Morgan Sindall.
The 250-acre site will be home to a new waterfront district of 11,500 new homes, focussed around a proposed new DLR station in the heart of the development.
Mayor of London, Sadiq Khan instructed TfL in 2017 to carry out detailed work on a DLR crossing connecting east and south-east London.
Dan Labbad, CEO at Lendlease, Europe, said: “As one of London’s largest areas of opportunity to develop new housing and to support business and employment growth, Thamesmead can offer a fresh approach to living in London.
“Surrounded by water and outstanding wildlife, but within reach of the heart of the capital, we are excited at the opportunity to collaborate with Peabody, the local community and businesses, to bring new high-quality homes and workspaces to this exciting part of south-east London”.