Kate Middleton's super-cute nickname for Princess Charlotte is adorable!

Oh, this is cute!

Kate Middleton has revealed the super-sweet nickname she has for her daughter, Princess Charlotte.

The Duchess of Cambridge let her little girls' nickname slip while on royal tour of Belfast, Northern Ireland.

The 37-year-old stopped to talk to blogger Laura-Ann and her son, asking her what her son's name was, which was George just like her eldest son.

“Hello, what’s your name?” Kate asked the little boy. "Hi George, what a cool name you’ve got, and you look very smart. It’s very nice to meet you."

Laura-Ann then revealed that Kate asked how old her other son was, "And I said he is 4 and she said, ‘Oh, he’s the same age as Lottie,'

She calls Princess Charlotte,  Lottie!"

Another fan, Kathryn Ward, revealed that Kate and Prince William said they have moments of sleep deprivation, thanks to raising three small kids - the youngest being Prince Louis who is nearly a year old!

"They were chatting a bit about sleep deprivation. Even though they get the help that they have, they’re still parents as well and want to get up with their own kids," Ward shared. "So they understand the stresses and pressures were going through, even though they got a couple of people more hands on. They were fantastic. Really on our level."

The royal family always have some brilliant nicknames for each other - and we hear about them by accident! 

• Prince George calls Prince William ‘Pops’
• Prince Harry has a very reportedly calls Kate Middleton, the Duchess of Cambridge, ‘Cath’
• Unsurprisingly, Prince Harry refers to his wife, Meghan Markle, as 'Meg' 
• Kate has also been heard to call Charlotte 'Poppet'
• Prince George has a supercute nickname for Prince Charles - Grandad Wales.

Do you have a nickname for your child?