There will be an extra tea-time service northbound and an extra evening service southbound.
However, it is understood three fast train services from London are being replaced by slower trains.
Virgin customers travelling between the capitals will see four new services daily in each direction from May 16, ensuring a half-hourly frequency throughout most of the day. Two additional services will be added on Sundays.
The timetable boost is expected to lead to an upsurge in cross-border travel and comes as Virgin Trains undergoes a £21m refurbishment of its fleet – including brand new leather seats in first class, new standard class seating, carpets and lighting.
Tickets for the new services will go on sale later this week after the Office of Rail and Road approved Virgin Trains’ timetable plans.
To celebrate the introduction of the services, Virgin Trains is releasing thousands of £25 Edinburgh-London fares (in each direction) for the new timetable, which will see 25 southbound services per weekday from Edinburgh. These will be on sale for two weeks from this Friday.
In a further innovation, Virgin Trains is extending the booking horizon during which it is possible to book tickets from the industry standard of 12 weeks to 24 weeks, making it easier to plan ahead for holidays, visits and other trips.
The move has been welcomed by the UK and Scottish governments’ respective transport ministers.
UK Rail Minister Claire Perry said: “This is welcome news for passengers travelling between Edinburgh and London and demonstrates that Virgin Trains are delivering on their commitment to bring extra services and seats to this important route.
“The UK government knows how important the railways are to keeping Britain connected, which is why we are investing over £38 billion on the network in this parliament.
“The increase to Scottish services is evidence that this franchise is delivering real improvements for passengers.”
David Horne, Virgin Trains’ managing director on the east coast route, said: “This is a major boost for our customers travelling between Edinburgh and London who will be able to catch a train every half-hour for most of the day.
“We have seen how increasing capacity and frequency adds to the popularity of train travel and we’re confident that customers will respond positively to these changes.”