Motor Racing Correspondent Jonathan Legard reports

The oval track will be altered for the event, with a new winding section in the infield.

The last US Grand Prix was won by Ayrton Senna at Pheonix in 1991, but American fans have never been as enthusiastic about F1 as the rest of the world.

Indy-car racing is more popular and the world famous 2.5 mile oval circuit at the Indianapolis Motor Speedway (IMS) already hosts what was traditionally the championship's main event, the Indy 500.

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But recent years have seen a feud within this sport, and the speedway has split from the main CART series, devaluing the race.

The Grand Prix gives the IMS a major international race, and fills a major hole in the US for F1.

Other cities believed to have made bids were San Francisco, Las Vegas and Atlanta, but the IMS has the history, facility and money to put on the event.

Speedway president Tony George said: "This is a project that we have pursued since 1991, and is now about to become a reality."

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The IMS used to be used exclusively for the Indy 500 but since 1994 it has spread its wings, hosting a race in the popular NASCAR series and also the International Race of Champions series this year.

"Our vision as a company is international leadership in motorsport entertainment, and the US Grand Prix underscores the reality of that vision," George said.

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The addition of a road course to the oval will be the first major alteration there since 1909.

F1 Chief Executive Bernie Ecclestone said: "I know the Speedway will look after us and see that we have a home for Formula One for years to come."

Bernie Ecclestone appeared at the announcement by TV link

The GP race will start on the main straight and use one of the oval's bends, but the next 12 corners will be brand new.

The cars will then run clockwise on the oval, which is the reverse of the direction used for the Indianapolis 500.

Kevin Forbes, who designed the course, said the infield holes of the Brickyard Crossing golf course will not be affected.

Work on the multi-million dollar project has already begun with the removal of part of a grandstand for F1 garages to be built.

Date debate

A decision on where the race will sit in the GP calendar has yet to be made.

The speedway prefers September or October but F1 teams are reluctant to make two trips across the Atlantic in a season and they want a weekend near the Canadian GP in June.

The problem for the circuit is that this is too close to the Indy 500's traditional date on the final Sunday of May.

Gerhard Berger in a McLaren at Pheonix in 1991

Grand Prix racing in the US has had a chequered history.

Watkins Glen, Long Beach, Detroit, Dallas and Pheonix have all staged races, but all of them stopped for one reason or another.

The GP circus is keen to become genuinely an world championship and move more from its European heartland to Asia and America.