Town’s third-v-first clash with Sheffield Wednesday at Portman Road on Saturday will be watched by a 29,000 sell-out crowd.
The Owls are bringing 2,100 supporters to Suffolk, the teams having drawn 2-2 at Hillsborough earlier in the season.
Town's have had one attendance in excess of 29,000 so far this season, 29,069 having watched the 1-1 draw with Plymouth last month.
The second-placed Pilgrims, who were beaten 1-0 away by Wednesday last weekend, are at home to Portsmouth on Saturday, while Derby in fourth are away against Wycombe Wanderers and Bolton, fifth, are at Peterborough.