A number of Amy's high profile guests, who were close to Stephen, will have to pull out of the wedding.
Among those who were due to attend were Westlife star, Nicky Byrne and his wife, Georgina Ahern, Cecelia Ahern and her actor boyfriend, David Keoghan, Bertie Ahern and Ronan Keating and his wife, Yvonne, to name but a few.
A family insider explained how Ronan has since pulled out of attending the wedding, while Nicky, the husband of Amy's first cousin Georgina, may make it to the reception but more than likely won't be at the church.
"It's very unfortunate that the wedding was pre-booked for that day but there's no way of changing it now," the source said.
"The hotel and the church were booked months ago and they would have to postpone until next year if they went down that route.
"Obviously Amy and Colm completely understand why some of the better known guests might not make it and they have expressed their deepest sympathies to the Gately family.
"Bertie will still be attending but he will also be making an appearance at the funeral, probably on Friday night," they added.
Amy and her other half have been going out for almost 10 years and have two 13-month-old twin boys, Pierce and Thomas.
Afterwards the bridal party will decamp to Barberstown Castle to continue the celebrations in style.
Proud dad and former Lord Mayor Maurice Ahern said: "They've been going out a long time so we've all been waiting for the day out."