Together with resignalling works and on-going Thameslink improvements, the scale of investment will soar to £800m around the busy London station site.
The plans include a new concourse that is bigger than the pitch at Wembley, which will sit underneath the tracks.
Two new entrances will be constructed on Tooley Street and St Thomas Street, which will improve links between the areas around the station.
Network Rail said it hopes to have a main contractor on board by the end of the year. Although the huge station rebuild will not start until after the Olympics to avoid disruption during the games.
The revised plans – like the previously approved scheme – include the demolition of the historic South Eastern Railway office building on Tooley Street.
Coupled with changes and improvements to the rail infrastructure around the station, the investment in the area will mark the final phase of the Thameslink programme to deliver longer trains and more frequent services to more destinations.
The station remodelling will involve the untangling a spaghetti of railway lines. This will increase the number of tracks going through the station from six to nine and a reduce from nine to six the number of terminating platforms.
Next weekend Skanska will complete an important part of the London Bridge Thameslink work when it slides a 1,200t bridge section into place.
The final 72m section of the replacement Borough viaduct has been built above the existing bridge to allow it to be jacked down into place.
Work is also already underway to improve the station, with the Shard tower development funding a new bus station – part of the London Bridge Quarter improvements – and delivering a new entrance and upper concourse for the train station.