It’s unclear how long Kate—who shares kids Prince George, 10, Princess Charlotte, 8, and Prince Louis, 5, with Prince William—will need to do preventive chemotherapy for. However, she said in the video that her cancer diagnosis has been challenging to navigate.

“This, of course, came as a huge shock,” Kate admitted, “and William and I have been doing everything we can to process and manage this privately for the sake of our young family.”

“As you can imagine, this has taken time,” she continued. “It has taken me time to recover from major surgery in order to start my treatment. But, most importantly, it has taken us time to explain everything to George, Charlotte and Louis in a way that is appropriate for them, and to reassure them that I am going to be OK.”