The two La Liga giants played out a 1-1 draw in the first leg last month, which leaves the tie delicately poised with at least 90 minutes of football to come.
The Catalan outfit are currently on a 22-match unbeaten run on their own patch, however, while Real Madrid's away form this season has been far from spectacular, with five league defeats on the road.
Barcelona have won just one of their last six matches against Real Madrid, but are on course to regain the La Liga title this season. They currently sit top of the standings with 68 points, 16 clear of third-placed Real Madrid.
The world's best two players will also be keen to impress on Tuesday with Lionel Messi scoring 17 goals in his last 23 games against Real Madrid, while Cristiano Ronaldo has seven in his last seven Clasicos.
The winner of the tie will advance to the final of the competition, where they will meet either Atletico Madrid or Sevilla, who clash on Wednesday.
Real Madrid: LWDWW
Barcelona: Valdes; Alves, Pique, Puyol, Alba; Xavi, Busquets, Fabregas; Iniesta, Messi, Pedro
Real Madrid: Lopez; Arbeloa, Ramos, Pepe, Coentrao; Khedira, Alonso; Di Maria, Ozil, Ronaldo; Benzema
Sports Mole says: 3-2 (4-3 on aggregate)