Victory would give Dortmund a 14-point lead at the top.
The hosts have won 16 of their 20 league games this season and Dortmund coach Jürgen Klopp said Friday's match "puts football in the centre of attention like nothing else."
"We will defend ourselves with everything we have," Klopp told www.bvb.de, the club's official website ahead of the 137th meeting between the two sides. "Of course we don't see ourselves as the underdogs."
Despite losing at home to Hoffenheim last weekend, Schalke 04, 11th in the league, are showing signs of promise and will be looking to upset the hosts.
“Dortmund only drew their last home game (1-1 with Stuttgart) and they seem to be stronger away at the moment than they are at home," said Schalke coach Felix Magath.
But the Royal Blues boss is under no illusion about the task his side faces.
"Our opponents will be the next German champions," he said.
Magath, meanwhile, told Schalke fans that he cannot work miracles on a tight budget.
"I am not a magician. They won't find anybody who can do better than me," said Magath, whose team are 25 points behind Dortmund. "I was recruited to drive this club to the summit without huge financial means. If they can find someone who can do that in a year, I will hand over to them.”