Kate Middleton underwent abdominal surgery in January and at the time it was thought her condition was non-cancerous. Following the procedure, tests should cancer had been present and the Princess of Wales, 42, is now undergoing a course of preventative chemotherapy.
Kate will continue to recover out of the public eye and is therefore not expected to be present at the Easter Service. Speaking in a video message, Kate said she "looks forward to being back when I am able, but for now I must focus on making a full recovery".
She added that she is focussing on getting well and stronger every day "by focusing on the things that will help me heal; in my mind, body and spirits".
She explained how she and husband have been working hard to protect their young children, Prince George, Princess Charlotte and Prince Louis and explain her diagnosis in a way they will understand.