Why Kate might struggle with Harry's Christmas present this year

Christmas with the Windsors is a traditional, grand affair celebrated within the Queen's Sandringham estate.

But it also includes a little bit of fun as members of the royal family gift each other with joke presents.

They have pretty much everything one could imagine, so the custom of swapping gag gifts makes sense.

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However, this year the Duchess of Cambridge might be scratching her head for present suggestions for brother-in-law, Prince Harry.

One of her most memorable presents in the past was a 'Grow your own Girlfriend' doll the Duchess is reported to have given Harry during her first Christmas with the royals in 2011.

The cheeky gift costs around $7 and expands when you immerse it in water. The packaging says, "No more nagging," "I won't cost you a sent" and "I love Sunday footy".

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Back then, Harry didn't have a long-term girlfriend having recently split with long-term partner Chelsy Davy.

Davy accompanied Harry to William and Kate's royal wedding in 2011 and supposedly that is when she realised she wasn't cut out for a life married to the prince.

Kate's gag gift was intended to poke some gentle fun at Harry, who she's always shared a close relationship with.

Harry and Kate are said to be more like brother and sister and are frequently spotted having a good laugh during their joint public engagements.

Their special bond even saw Prince Harry seek the Duchess of Cambridge’s approval before marrying Meghan Markle.

But now Prince Harry is married – and will become a father next year – Kate's going to have to think a little harder for a joke present this Christmas.