The contract is for 102 Siemens 7MW turbines to go to the project, which is located in the North Sea off the east coast of England.
ScottishPower said the project will be commissioned in 2019 while construction will start in 2017.
According to Windpower Monthly's data division, Windpower Intelligence, ScottishPower's East Anglia One is consented for up to 1.2GW, as the first phase of the 7.2GW East Anglia Round 3 zone.
Siemens' manufacturing and assembly plant at Hull could have proved a factor in the deal.
Recent correspondence was uncovered by Windpower Monthly between Siemens and the UK government showed there would be some form of local sourcing policy in place. The blades will be manufactured at Siemens' Hull plant.
East Anglia One was initially being co-developed by Vattenfall and SPR, but it is now being developed solely by SPR. A phased development of 714MW is planned initially, but SPR may look to build out the full project by securing further capacity in future Contract for Difference subsidy auctions.
In a statement, Energy and Climate Change Secretary Amber Rudd said: "This massive financial investment is great news for East Anglia and for Hull, which will now become a real clean energy manufacturing hub.
"In addition to supporting thousands of UK jobs, this project shows we are driving down the costs of offshore wind; another demonstration of how the Government is developing the full potential of the offshore wind sector at the lowest cost to bill payers."