The 20,000 plus crowd breaks the previous Premiership record of 19,768 for the Saracens and Newcastle tie at Vicarage Road during the 1997-98 season.
Commenting on www.bristolshoguns.co.uk Shoguns commercial director Mike Turner said: "The sell out crowd is superb and will generate the best atmosphere anyone will have seen at a Premiership club game."
Turner added: "Sunday is going to be an occasion that many people will remember for a long time."
Bristol Shoguns are advising all supporters to arrive at the game as early as possible with turnstiles opening at 1.30pm. With all tickets sold for the game the club is advising anyone without a ticket not to travel to Ashton Gate.
There will be pre-match entertainment from the Royal Gloucestershire, Berkshire and Wiltshire Regiment (RGBW) and their Moonrakers Freefall parachute team, who will be dropping in before the kick-off (subject to weather conditions).
In addition, supporters will also be entertained by the Lucknow Band of the Prince of Wales' Division.
