Former Taoiseach John Bruton has been confirmed as the guest speaker at the opening day of this year's Knock Novena.
The annual Novena attracts thousands of pilgrims each day for the 9 days of the event.
This year marks the 140th anniversary of the Apparition at Knock, and the theme for the Novena is "Continuing Our Journey".
John Bruton, who served as Taoiseach from 1994 to 1997, is the guest speaker on the first day of the Novena, on the theme "Faith, Future and Europe".
Olive Foley, widow of the late Munster rugby player Anthony Foley, RTE reporter Carole Coleman and former Green Party TD and recently-ordained Reverend Trevor Sargent are among the speakers taking part in this year's National Novena.
A number of religious speakers - including the Bishops of Elphin and Raphoe will also address pilgrims during the Novena, with ceremonies at 3pm and 8pm each day.