The British royal issued the update on her health journey in an intimate video released by Kensington Palace, in which she reflected on her "incredibly tough" year.

In the video, which was filmed last month in Norfolk, Prince William's wife told her subjects ... "As the summer comes to an end, I cannot tell you what a relief it is to have finally completed my chemotherapy treatment."

While the Palace did not confirm whether the princess is officially cancer-free, Princess Kate noted her "path to healing and full recovery is long" ... stating she plans to take "each day as it comes."

Nonetheless, the royal, who took a step back from public appearances after announcing her cancer diagnosis in March, is expected to step out more later this year. She will reportedly attend the annual Remembrance service at the Cenotaph in London -- a war memorial remembering those lost in wartime -- in November.

Her first public appearance in 2024 came at the Trooping the Colour Ceremony in June ... where she joined the other royals at the famous Buckingham Palace. She stepped out again in July looking happy and healthy for a day at Wimbledon ... where she received a standing ovation.

It still remains unclear what type of cancer Princess Kate battled this year ... but in her new update, she referred to her health crisis as "complex, scary and unpredictable."

Kate's health struggles began back in January ... when she was hospitalized requiring abdominal surgery. After much speculation, the princess later confirmed she was battling cancer ... and asked for privacy for herself and her children, Prince George, Princess Charlotte, and Prince Louis.

Now, the Royal Highness appears optimistic about her future, telling her followers that she now has a "renewed sense of hope" heading into the fall.