Technically, the Lenten fast ends just before the Evening Mass of the Lord's Supper when the sacred Triduum begins and at which time the Easter fast begins.
In Paschale solemnitatis, the circular letter concerning the preparation and celebration of the Easter feasts, Mother Church reminds us of the following:
The Easter fast is sacred on the first two days of the Triduum, in which, according to ancient tradition, the Church fasts "becasue the Spouse has been taken away." Good Friday is a day of fasting and abstinence; it is also recommended that Holy Saturday be so observed, so that the Church, with uplifted and welcoming heart, be ready to celebrate the joys of the Sunday of the Resurrection (39).
Just as we must avoid the temptation to celebrate Christmas during Advent, we must avoid the temptation to celebrate Easter before it has arrived. We are Catholic, afterall.