BBC's Christmas special show "A Berry Royal Christmas" will air on BBC One on Monday. Kate Middleton has revealed that her youngest child Prince Louis's first word was "Mary". The Duchess of Cambridge said this while having a conversation with Mary Berry.

"One of Louis' first words was 'Mary', because right at his height are all my cooking books in the kitchen bookshelf. And children are really fascinated by faces, and your faces are all over your cooking books and he would say 'That's Mary Berry' ... so he would definitely recognise you if he saw you today," said Kate during her Christmas TV special with "The Great British Bake Off" star Mary Berry.

Prince William and Kate Middleton's youngest child Prince Louis will turn two next year. The 19-month-old tot delighted royal fans when he made his debut on the Buckingham Palace balcony at Trooping the Colour in June. His older siblings Prince George, six, and Princess Charlotte, four, were also present.

The 84-year-old Berry will take to the kitchen with Kate and William, both 37, to rustle up a series of festive treats for the royals' charity staff. In the one-hour special, Berry spoke about her admiration for the royal couple's love for one another, comparing it to the bond shared by pigeons, who mate for life, Hello reports.

In "A Berry Royal Christmas", she also reflected on her impression of the Duke and Duchess of Cambridge, after joining them on four engagements, including two to charities they support.

"They don't just arrive and shake a few hands, make a few smiles and a speech, they want to get involved, and they want to see what they can do. And it isn't just one visit, they come back again and ask for the results and they remember who they spoke to last time. I think that's remarkable," she said.

#ABerryRoyalChristmas culminates in a Christmas party, hosted by The Duke and Duchess of Cambridge, to thank and acknowledge staff and volunteers from charities and organisations who will be working tirelessly over the Christmas period.

📷 @mattporteous pic.twitter.com/dj0eZY7vJy

— Kensington Palace (@KensingtonRoyal) November 30, 2019

Berry visited The Brink, the UK's first dry bar set up by one of Kate's patronages Action on Addiction in Liverpool. In September, the former Bake Off judge also joined the duchess at RHS Wisley for a tour of a new space, inspired by her Back to Nature garden. With William, she visited The Passage, a charity which helps the homeless.

The Christmas special will culminate in a Christmas party, hosted by William and Kate at the Rosewood Hotel in London in October.

kate middleton
Kate Middleton wears a Jenny Packham gown at the Baftas Getty

This was the royal couple's way to thank the charity workers and volunteers who will be working over the festive season. The festive menu curated by Berry consisted of beetroot and chocolate cake, stilton and fig tartlets, beef stew with ginger and horseradish and stained glass biscuits. Besides these was a special mocktail.

"A Berry Royal Christmas" airs Monday at 8:30 pm on BBC One.