Scheduled to be completed in 2019, the Nemo Link will enable energy trades and flows between the two markets.
Belgian Energy, Environment and Sustainable Development Minister Marie-Christine Marghem said: "The project that our two transmission system operators (TSOs) have just launched is part of the Belgian energy vision and is in line with a European Energy Union, where the implementation of interconnectors is a prerequisite for the security of supply and the reinforcement of the competitiveness of Europe and Belgium in particular."
Project Nemo will run 140km between Zeebrugge in Belgium and Richborough in Kent.
UK Energy and Climate Change Secretary Ed Davey said: "Better electricity links to our neighbors help to guarantee our energy security at the lowest possible cost to billpayers and means we can use renewable electricity more effectively, allowing excess generation to be exported.
"This new interconnector will increase the amount of capacity available through interconnectors by 25%."
Elia and National Grid are planning to sign contracts for the construction of the converter stations and cable laying for the project, soon.
The engineering design and site preparation works will be carried out later this year.
Belgium is currently importing 3.5GW of electricity and is planning for an additional 1GW interconnection with Germany.
The UK currently has a 2,000MW interconnector with France and 1,000MW link to the Netherlands in operation.
