Four-year-old Sienna (left in picture) has acute lymphoblastic leukaemia.
For such a young person, she has been through so much and has had to edure a lot of time in hospital.
Her greatest wish was to be a princess and so Starlight organised a very special day for Sienna and sister Saffron.
The girls were taken to The Enchanted House in London where they were given makeovers, then they were dressed in brand new dresses and given their own wands. Next it was time for a party lunch and then they were picked up in a Limo and taken to the theatre. Phew! A hard life being a princesses!