Eurosport - Sun, 07 Mar 18:10:00 2010
The game will be a rematch of the 2000 final, the last to be played at the old Wembley, which the Blues won 1-0.
Villa, who came from two goals down to win 4-2 at Reading in the quarter-final, beat Chelsea 2-1 at Villa Park earlier in the season, with the two also due to meet in the Premier League at Villa Park at the end of March.
Chelsea cruised into the last four with a 2-0 win over Stoke at Stamford Bridge.
Portsmouth, who won the Cup in 2008 and beat Birmingham to get this far, are in administration and lie bottom of the Premier League, will provide the opposition for Spurs or Fulham after they drew 0-0 at Craven Cottage.
The semis are due to be played at Wembley Stadium on April 10 and 11.