Formula One supremo Bernie Ecclestone had given the British Racing Drivers Club (BRDC) - owners of the track - until Thursday to agree a deal and BRDC president Jackie Stewart confirmed the deal had been done.
"The announcement (of the race date) will be confirmed tomorrow in Monte Carlo," Stewart told Sky News television.
The official 2005 calendar is due to be ratified by the governing International Automobile Federation (FIA)'s world motor sport council in Monaco on Friday.
The 74-year-old Ecclestone, who draws up the calendar and controls the sport's commercial rights, had said there had to be a contract before the race can be listed.
Britain has hosted a Grand Prix every year since the first Formula One championship race at Silverstone, a former World War Two airfield, in 1950. Six of the 10 teams are based in England.
