Albion, who are seventh in the Premier League and on track for European qualification, advanced to the last four thanks to their thumping 5-0 quarter-final win against League Two Grimsby Town at the Amex Stadium last month.
Brighton are in fine form at the moment and arrive at Wembley on the back of a 2-1 away win at midtable strugglers Chelsea. Man United however will be a tough test and are currently one of the best teams in the top flight at the moment. Erik ten Hag's men are third in he league and last Sunday enjoyed a comfortable 2-0 win against Nottingham Forest.
Meanwhile, in the other semi-final clash, title-chasing Man City take on Championship promotion hopefuls Sheffield United on the Saturday. A cup run is a huge boast for the fans and also provides healthy income for the club once they reach the later stages of the competition.
Here's the total prizemoney earned so far – looking at each round and how much they stand to win should they reach the final and then lift the trophy...
Meanwhile, in the other semi-final clash, title-chasing Man City take on Championship promotion hopefuls Sheffield United on the Saturday. A cup run is a huge boast for the fans and also provides healthy income for the club once they reach the later stages of the competition.