ACTED LAWFULLY AND WERE EXERCISING THEIR RIGHTS TO FREE SPEECH. >>> CATHERINE, PRINCE OF WALES, ANNOUNCED SHE FINISHED SIX ROUNDS OF CANCER TREATMENTS. SHE SPOKE ABOUT HER BATTLE WITH THE ILLNESS IN A VIDEO WITH HER HUSBAND AND THREE CHILDREN. TINA KRAUS HAS MORE FROM LONDON. >> Reporter: KENSINGTON PALACE RELEASED A RARE AND INTIMATE LOOK AT PRINCESS KATE'S FAMILY LIFE AS SHE BATTLES CANCER. >> I CANNOT TELL YOU WHAT A RELIEF IT IS TO FINALLY HAVE COMPLETED MY CHEMOTHERAPY TREATMENT. >> Reporter: THE 42-YEAR-OLD ANNOUNCED IN MARCH SHE WAS BEING TREATED FOR AN UNDISCLOSED KIND OF CANCER FOUND DURING AN ABDOMINAL SURGERY IN JANUARY. >> WE'VE HAD TO FIND A WAY TO NAVIGATE THE STORMY WATERS. >> Reporter: THE MOTHER OF THREE SAID THE DIAGNOSIS GAVE HER A NEW PERSPECTIVE ON EVERYTHING. THE NEW VIDEO SHOWS 11-YEAR-OLD GEORGE, 9-YEAR-OLD CHARLOTTE, AND 6-YEAR-OLD LOUIE ENJOYING LIFE WITH THEIR PARENTS NEAR THEIR FAMILY HOME IN EASTERN ENGLAND. ONE SCENE SHOWS KATE'S PARENTS PLAYING CARDS WITH THEIR GRANDCHILDREN. >> THIS TIME HAS ABOVE ALL REMINDED WILLIAM AND ME TO REFLECT AND BE GRATEFUL FOR THE SIMPLE, YET IMPORTANT THINGS IN LIFE WHICH SO MANY OF US OFTEN TAKE FOR GRANTED AS SIMPLY LOVING AND BEING LOVED. >> Reporter: EIGHT WEEKS AGO KATE THRILLED CROWDS WHEN SHE VISITED WIMBLEDON AND GOT A STANDING OVATION AT CENTER COURT. THE PRINCESS PLANS TO CARRY OUT A FEW ROYAL DUTIES LATER THIS YEAR BUT SAYS HER FOCUS NOW IS DOING WHAT SHE CAN