Manchester United 2 - 1 Tottenham Hotspur
Ander Herrera has sent Manchester United into a record-equaling 20th FA Cup final, after his goal proved the difference in his side's 2-1 victory over Tottenham Hotspur.
Spurs started with pace and ferocity and fully deserved their 1-0 lead after 11 minutes when Dele Ali scored off a sublime Christian Eriksen cross.
After United survived Tottenham's seige, Wembley specialist Alexis Sanchez headed home a Paul Pogba cross, to score his eighth goal in eight appearances at the venue to level the scoring.
With the scores level at half time, after an Eric Dier strike hit the post, Herrera's low finish just after the hour mark set up an FA Cup final date.
Tottenham's defeat means that they now have lost their past eight semi final matches in the FA Cup and leaves manager Mauricio Pochettino without a trophy in his first four years at the club.
Chelsea 2 - 0 Southampton
Goals to Olivier Giroud and Alvaro Morata have ensure a date with Manchester United in the FA Cup final, after Chelsea easily accounted for Southampton.
After Giroud opened the scoring by finding his way past two players and the goalkeeper in a crowded area in the 46th minute, Morata replaced Giroud with 10 minutes remaining and but the result beyond doubt after a Cesar Azpilicueta's cross found Morata on the back post.
Southampton came close to equalising, with Charlie Austin coming the closest when he hit the post, however the result never really look beyond doubt.
The clash at Wembley will be the first time they've met in an FA Cup final since 2007, when Mourinho guided Chelsea to a 1-0 victory over United.