Steve Cotterill's City side are top of League One and undefeated this term and Hanks knows the size of the task facing Mark Yates' men.
But he says they are determined to give a good account of themselves in front of the live Sky TV cameras and under the floodlights at Whaddon Road.
"Any game against a team in the league above is always a big one, especially with it being on TV," Hanks said.
"It’s a massive game for us and the supporters so we are really looking forward to it.
"Hopefully we can cause a little upset and we’ll be doing our best to achieve that. I don’t see why we can’t do it.
"We all know Steve Cotterill is coming back to his home town club, but as players we are focusing on the job in hand, which is playing well against his team.
"I think we have a good chance. The boys will be so up for it and anything could happen."