The feast of the Annunciation is normally celebrated on 25 March, nine months before the celebration of the birth of Jesus on 25 December. This year, it was moved to 4 April, since Good Friday fell on 25 March. Some saw an opportunity to connect the conception of Jesus with his death, but the liturgical calendar gives a separate day for the Annunciation.
More on the Annunciation can be found on the BBC web site.
The collect for the feast of the Annunciation:
We beseech you, O Lord,
pour your grace into our hearts,
that as we have known the incarnation of your Son Jesus Christ by the message of an angel,
so by his cross and passion
we may be brought to the glory of his resurrection;
through Jesus Christ your Son our Lord,
who is alive and reigns with you,
in the unity of the Holy Spirit,
one God, now and for ever. Amen.