The Bluebirds booked their place at Wembley with a penalty shootout win over 10-man Crystal Palace, with Heaton pulling off two impressive saves from the spot.
This got us thinking about how many ex-Reds have appeared at the new Wembley in a domestic cup match since the stadium was opened in time for the 2007 FA Cup final.
Having looked at the line-ups for the four League Cup finals and thirteen FA Cup semi-finals and finals, we've come up with the names of NINE ex-United players. Did you work out who they were?
Jonathan Greening: West Brom v Portsmouth in 2007/08 FA Cup semi final
Mikael Silvestre: Arsenal v Chelsea in 2008/09 FA Cup semi final
Tim Howard: Everton v Chelsea in 2008/09 FA Cup final
Phil Neville: Everton v Chelsea in 2008/09 FA Cup final
Louis Saha: Everton v Chelsea in 2008/09 FA Cup final
Ben Foster: Birmingham v Arsenal in 2010/11 League Cup final
Carlos Tevez: Man City v United and Stoke in 10/11 FA Cup semi final/final
Ryan Shawcross: Stoke v Bolton and Man City in 2010/11 FA Cup semi final/final
Danny Pugh: Stoke v Bolton and Man City in 2010/11 FA Cup semi final/final