The four-year-old currently attends the £14,000 a year Willcocks Nursery School in South Kensington.
Simon O’Malley, Headmaster at Thomas’s Battersea, said: “We are delighted that The Duke and Duchess of Cambridge have decided that Princess Charlotte will join her elder brother, Prince George, at Thomas’s Battersea.
“We greatly look forward to welcoming her and all of our new pupils to the school in September.”
For a first child, the fees are £6,429 per term from Reception to Year 2.
There are added charges for extra curricular activities, such as ballet, drama and music lessons.
Charlotte is said to be keen fan of the ballet and has reportedly been taking private lessons already.
Thomas’s Battersea teaches around 560 boys and girls between the ages of four and 13. Their website states that their most important school rule is to ‘Be Kind.’
Their curriculum includes art, ballet, drama, ICT, French, Music and PE all taught by specialist teachers.
A nervous-looking George started his first day at school on September 7, 2017 and was dropped off at Thomas’s by dad William.
Kate missed the occasion because she was not well enough to take him. The duchess was suffering with hypremesis gravidarum (severe morning sickness) during her third pregnancy with Prince Louis.
George began his education in January 2016, at the Westacre Montessori School Nursery, near the family’s Norfolk home, Anmer Hall. The navy quilted John Lewis coat he wore sold out within minutes.
Last Sunday, the palace released photos of the Cambridges as a family of five as they explored Kate’s ‘Back to Nature’ garden at the Chelsea Flower Show.