David & Harper Beckham. Picture: Instagram

Harper Beckham attended a tea party at Buckingham Palace last week.

The six-year-old daughter of David and Victoria Beckham wore a gown inspired by Queen Elsa from the movie 'Frozen' for the bash at the royal residence, where she spent time with the likes of Princess Eugenie and a host of her school friends.

Harper celebrates her birthday today (10.07.17) and to mark the occasion, David has posted a glowing tribute to his daughter on Instagram.

READ: SHOULD PARENTS KISS THEIR CHILDREN ON THE LIPS?

Alongside a snap of the pair at the Palace, the retired soccer star wrote: "Happy Birthday to our special little young lady ...Such a special girl who brings so much joy and happiness into our lives.. Happy 6th birthday ( I can't believe your 6 already ) have the most amazing day we love you pretty lady x (sic)"

In a subsequent post, David shared a picture of Harper and her friends with Princess Eugenie - the younger daughter of Prince Andrew and Sarah, Duchess of York - at the Palace, where a number of schools were recently invited to visit.

He captioned the image: "Lucky Harper meeting a real life princess at the Palace x (sic)"

Meanwhile, Victoria also posted a snap of Harper holding a red balloon while stood outside the world-famous landmark.

The fashion designer wrote: "Our little birthday princess x Kisses (sic)"

This comes shortly after David revealed that his three sons - Brooklyn, 18, Romeo, 14, and Cruz, 12 - have already developed a protective attitude towards their little sister.

David admitted he's dreading the day Harper starts dating, but he knows the boys will be on hand to help him out.

He said: "Luckily, she's got three older brothers as well. So once she starts dating, that person will have to go through an inspection with her brothers [and] her dad. It'll be tough."