More from: Brits among finalists for Barcelona FC work
The competition-winning scheme, which was unveiled by the Catalan club on Saturday, will expand the seating capacity of Europe's largest stadium from 98,000 to 106,000 seats.
The most noticeable change, however, will be the multi-coloured 'skin', made up of overlapping translucent tiles, which will wrap around the building and continue over the roof.
According to the practice, 'the myriad tiles can be seen as symbolising the loyalty and devotion of Barcelona's fans worldwide'. Powered by photovoltaic panels, at night this facade will glow in Barcelona colours and will feature animated effects to give the stadium 'a changing image and dynamic response to environment and events' - an echo of Herzog & de Meuron's Allianz stadium in Munich.
Other plans include improving circulation along escalators; new escape stairs; a bigger museum; and a large basement housing a loading bay, a service ring road and stores.
Elsewhere, the proposals will retain much of the original Nou Camp, designed by architects Francesc Mitjans-Miró, García Barbon and Soteras Mauri - opened almost exactly 50 years ago.
Foster, said: 'It is an enormous honour to have been selected to remodel Nou Camp Stadium for Barcelona, such an important symbol for the Barca fans and the Catalan people.
'Football is a powerful and democratic force that brings together all social classes in celebration; therefore a stadium, perhaps more than other type of building, is a truly democratic space - the design of a stadium is the greatest expression of an architecture that goes beyond aesthetics to have a social agenda.'
He added: 'In this sense I believe that there is a wonderful connection between football and architecture.'
The stadium project is due to complete in 2011.
Foster unveils extension to the Nou Camp - Europe's largest stadium