The trains, which will be launched in 2018, will enable passengers make the journey in four hours.
They will accelerate from 0-125mph around a minute quicker than the current fleet.
Sir Richard Branson, founder of the Virgin Group, unveiled the first of the new trains at London King's Cross.
The 65 new trains will be built by Japanese firm Hitachi at its manufacturing plant in Newton Aycliffe, County Durham.
They will be named Virgin Azuma, which is the Japanese translation for "east".
Sir Richard said: "This is a hugely important moment for passengers on the East Coast.
"A line which has witnessed the historic Flying Scotsman and Mallard will now see passenger services transformed with the UK's most advanced long distance trains.
"Our customers on the West Coast have already seen what Virgin can bring to train travel and how the Pendolinos have made a huge difference to speed and comfort.
"Our new fleet of Azumas will bring a similar transformation to the East Coast, and propel one of the UK's most prestigious lines into the 21st Century."
Virgin said the trains would provide 12,200 extra seats and increase peak-time capacity into King's Cross by 28%.
It is working with Network Rail and other industry bodies to investigate the potential for the East Coast route to be upgraded to allow trains to operate at 140mph.
The interior of the Azumas has not been finalised, but Virgin claimed they will offer some of the best leg-room on the network, faster and free wi-fi, an enhanced system for highlighting reserved seats and more overhead luggage space.
Transport Secretary Patrick McLoughlin said: "The state-of-the-art Intercity Express trains heading to Virgin will transform rail travel for passengers between London, the North East and Scotland.
"These new trains, combined with Virgin's exciting plans for the franchise, will provide more services, more seats and faster journeys, helping to place passengers at the heart of the railway."
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