The former Monchengladbach star is eagerly anticipating the semi-final tie and believes his side can spring a surprise if they keep up their recent form
The Germany international believes the Spanish giants start the tie as favourites, but has stressed that BVB have nothing to lose and are brimming with confidence.
"To be honest, I'm very optimistic about the game. I'm feeling very positive," Reus was quoted as saying by Marca.
"We've won the last four games we've played and we're still unbeaten in the Champions League. No team has beaten us yet. So there's no reason to doubt Borussia and think this success story won't continue.
"But we obviously have great respect for Real Madrid. It's a really great team. Obviously Real Madrid is the favourite, but we're elated and there's no doubt that we have nothing to lose.
"We have the ability to put our egos to one side and act as a group. As for football, our pressure, speed and the way we play the ball make us a special team."
Wendesday's encounter at the Signal Iduna Park is scheduled to kick off at 20:45CET.