The fixture has moved from Saturday, May 4 (15:00 BST kick-off) to Sunday, May 5 (14:00 BST kick-off).
Aston Villa, who are bidding to reach a first European final in 42 years and are the Premier League’s sole remaining representative in UEFA club competitions this season, host Olympiacos on Thursday, May 2 at 20:00 BST in the semifinal, first leg, before the return leg in Greece seven days later.