The second cousins are to be baptised at the Royal Chapel of All Saints in Windsor Great Park.
And the Queen could be in attendance following time off work according to one royal source.
The source said: “Her Majesty is very keen to be there as she knows how important this is for her grandchildren and great-grandchildren.”
Royal christening: Princess Eugenie and Jack Brooksbank’s son was born in February
Kate, Duchess of Cambridge and Prince William are thought to be attending, as are Eugenie’s parents Sarah, Duchess of York and Prince Andrew.
Following advice from her doctor the Queen missed out on Remembrance Sunday services, and she is said to be consulting her doctor before officially agreeing to attend the christening.
The source told the Sun: “It’s set to be a heartwarming family occasion and a time of real celebration after what has been some challenging times for certain royals of late, including the Queen herself.
“She is keen to attend such a wonderful event after the great personal disappointment of missing last Sunday’s Remembrance events.”
Royal christening: Zara Tindall and Mike had baby Lucas in March
Royal christening: Royal babies wear the honiton gown when they are christened
Royal christenings are steeped in tradition, and both Princess Eugenie and Zara face a tricky decision ahead of the christening.
Royal babies are christened using the Lily Font and wearing a replica of the Honiton Gown.
However, with two babies being christened at the same time, the royals need to decide who will wear the iconic gown.
It could be Eugenie and Zara decide not to use the gown entirely, or even swap between christenings depending on the order of service.
The original Honiton Gown was commissioned by Queen Victoria for her daughter Princess Victoria in 1841.
With inspiration from Queen Victoria’s wedding dress, the gown was made with white silk and a handmade lace overlay.
The original gown was worn by 62 royal babies across 163 years, before being retired after Lady Louise Windsor’s christening in 2004.
A replica was made by the Queen’s personal wardrobe advisor, Angela Kelly and subsequently worn by the next generation of royal babies.
The Lily Font has been used for the baptism of all the children and grandchildren of Queen Elizabeth II except Princess Eugenie’s.
Made from silver gilt, the font’s bowl is in the form of an expanded flower with a border of water-lilies and leaves.
The stem is formed of leaves, flanked at the base by three seated cherubs playing lyres upon a circular plinth with coats of arms and supporters.
Source: EXPRESS CO UK