The consecration will be a renewal of the original offering made by Cardinal Bernard Griffin on July 16th. 1948.
The National Pilgrim Virgin Statue and Relics will arrive at 1.45pm on Saturday and remain in the Cathedral until 2.30pm the following day.
After Mass people will be invited to venerate the relics and participate in Marian devotions.
This will be followed by a Fatima Symposium in Westminster Cathedral Hall.
2017 marks the 100th anniversary since Our Lady first appeared to two children in Fatima, Portugal.