The identity of the godparents will be revealed when Charlotte is christened at 3.30am Monday New Zealand time at the church of St Mary Magdalene, Sandringham, with fewer than 30 guests.
Several thousand members of the public are expected to take up the Duke and Duchess's invitation to share in the day by standing in a paddock outside the churchyard.
They will have the opportunity to see the Duke, Duchess, Prince George and Princess Charlotte together in public for the first time.
The young princess will wear the same christening gown her brother wore when he was baptised in October 2013 - a replica of the gown that Queen Victoria's eldest daughter wore for her christening in 1841.
She will be baptised by the Archbishop of Canterbury, Justin Welby, using water from the River Jordan, where it's believed Jesus was baptised by St John.
The church is where Diana, Princess of Wales, was christened in 1961.
Prince William wanted Charlotte's christening to be as close as possible to his mother's birthday - Diana would have been 54 this Thursday.
The Royal Mint has unveiled a £5 commemorative coin featuring two harp-playing cherubs surrounded by swags of lilies.
The Queen, the Duke of Edinburgh, the Prince of Wales, Duchess of Cornwall and the Middleton family will be among the guests.
