Kick-off for the London derby at Wembley is scheduled for 5.15pm.
The second semi-final between Arsenal and Manchester City will take place on Sunday, April 23, at 3pm.
BBC One will be screening the Saturday clash live, with BT Sport taking in Arsene Wenger and Pep Guardiola's 11th meeting as managers.
Tottenham Hotspur 6-0 Millwall - Emirates FA Cup 2016/17 (R6) | Official Highlights
Chelsea and Tottenham last met in an FA Cup semi-final five years ago, with the Blues running out 5-1 winners.
The Blues remain on course to become the first top-flight team to win a league and cup double since Carlo Ancelotti's 2009-10 side.
Spurs thrashed League One outfit Milwall 6-0 to reach the last four, with Chelsea knocking out holders Manchester United on Monday with a 1-0 win.
Arsenal - joint-record victors of the competition with 13 - are aiming to reach, and win, their third final in four years, while City lost to Wigan in their previous showpiece outing.