The match on Sunday 28 October will kick off at 1.30pm.
The other last-four tie between Aberdeen and Rangers will remain at Hampden on the same day, but will now kick off at 4.30pm.
The changes come after the Scottish Professional Football League came under enormous pressure to change its scheduling of the semi-finals.
Both ties were originally slated to be played on the same day at Hampden, provoking an outcry.
The plan was criticised by Hearts, Aberdeen, politicians, police federation officials and ScotRail, who said there had been a lack of consultation over the transport implications.
Police Scotland were also concerned and called for fresh talks over the plan to stage Aberdeen-Rangers at noon and the other tie at 7.45pm.
The SPFL has now bowed to pressure and moved the Hearts-Celtic game to Edinburgh while delaying the kick-off of the Aberdeen-Rangers tie to give supporters of the Pittodrie club more opportunity to travel to the match.