After receiving her CBE from Prince William, Ms Donaldson told ITV News that the proud father told her that Charlotte was having a 'rowdy party with lots of friends."
Plans for Princess Charlotte's birthday bash comes shortly after Kensington Palace released three new photographs for the fourth-in-line to the throne, taken by Kate Middleton, to mark the special occasion.
"Thank you for the lovely messages for Princess Charlotte's fourth birthday!," a statement from the palace read on Instagram.
Earlier this week while attending a royal engagement in London, the Duchess revealed her daughter loves playing with slime.
"Charlotte, my daughter, she dropped hers on the floor and it was pink and ended up brown and covered in so much mud," the mother-of-three told a young girl.
"It ends up all gooey."