Barcelona qualified for the last-four in dramatic fashion, beating Sevilla 6-1 in the second leg - overturning a first-leg 2-0 deficit.
While Los Blancos eased past Girona with a 7-3 aggregate scoreline. Now the two giants of LaLiga will meet in a mouthwatering double Clasico tie.
The first-leg tie will take place at the Camp Nou on 6/7 February with the second-leg to follow at the Santiago Bernabeu on the 27/28 February.
Spain's big two then meet in La Liga a few days later on Saturday 2 March.
Real Betis meanwhile were drawn against Valencia on the other side of the draw, giving the Andalusians a real opportunity of reaching the final which is being played at their own Benito Villamarín Stadium.
The semi-finals of the #CopaDelRey! ????@RealBetis_en ???? @valenciacf_en @FCBarcelona ???? @realmadriden
— LaLiga (@LaLigaEN) February 1, 2019
Who's going to reach the final? ???? pic.twitter.com/4tOiLUZTln
The Blaugrana are aiming for a record fifth consecutive Spanish League Cup title.