However, festival director Sean Doran received the unfortunate news that means she will no longer be appearing.
Doran said: "I heard from Winona last night that she had just lost a dear friend and would not now be able to come ... She was very apologetic and saddened... as she had been very much looking forward to taking part... It is of course a great shame that Winona will not be joining us this year."
He added that Ryder hopes to return to the festival next year.
The Happy Days Enniskillen International Beckett Festival, which takes place in the island town of Eniskillen, Northern Ireland – where Beckett spent his early schooldays – is the world's first annual festival to celebrate the life, work and influence of Samuel Beckett.
Ryder was due to be one of several celebrity guest speakers, or "tellers," who will read the author's work in a variety of locations throughout the town. Other celebrity tellers this year include Miranda Richardson, Juliet Stevenson and comedian Frank Skinner.
- Alex Gordon
The 2013 Happy Days Enniskillen International Beckett Festival runs from 22-26 August in Eniskillen, Northern Ireland.