Kate Middleton has completed her chemotherapy treatment for cancer.

The mother of three took to social media on Monday to share the update on her health.

“As the summer comes to an end, I cannot tell you what a relief it is to have finally completed my chemotherapy treatment,” the 42-year-old wrote. “The last nine months have been incredibly tough for us as a family. Life as you know it can change in an instant and we have had to find a way to navigate the stormy waters and road unknown.”

A still image of Kate Middleton with Prince William and their three children from a video in which she gives a personal update on her treatment and recovery. (Will Warr)

“The cancer journey is complex, scary and unpredictable for everyone, especially those closest to you,” she shared. “With humility, it also brings you face to face with your own vulnerabilities in a way you have never considered before, and with that, a new perspective on everything. 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. Of simply loving and being loved. Doing what I can to stay cancer free is now my focus.”

“Although I have finished chemotherapy, my path to healing and full recovery is long and I must continue to take each day as it comes,” the princess continued. “I am however looking forward to being back at work and undertaking a few more public engagements in the coming months when I can. Despite all that has gone before I enter this new phase of recovery with a renewed sense of hope and appreciation of life.

“Doing what I can to stay cancer free is now my focus.”

— Catherine, Princess of Wales

“William and I are so grateful for the support we have received and have drawn great strength from all those who are helping us at this time. Everyone’s kindness, empathy and compassion has been truly humbling. To all those who are continuing their own cancer journey – I remain with you, side by side, hand in hand. Out of darkness, can come light, so let that light shine bright.”

Kate Middleton focused on spending the summer with her family as she completed chemotherapy. (Will Warr)

In January, Kate underwent a planned abdominal surgery, which sparked speculation concerning her health. In March, Kate announced in a video that she had been diagnosed with cancer and was receiving chemotherapy.

The princess has kept a low profile throughout the year to focus on her recovery. She was only seen in an official capacity twice – on June 15 for Trooping the Colour and on July 14 at Wimbledon.

Kate Middleton previously admitted she had good days during her treatment, but there were tough days, too. (Will Warr)

In June, Kate admitted in a statement that while she has “good days,” chemotherapy also brought on tough days too. She also noted that her work brought her “a deep sense of joy.”

The Prince and Princess of Wales are seen here with their daughter, Princess Charlotte. The royal children are now back at school. (Will Warr)

According to People magazine, Kate quietly worked from Adelaide Cottage during the summer. The outlet shared that she had regular meetings with private secretary Tom White, assistant private secretary Natalie Burrows and the Prince and Prince of Wales’ communications secretary, Lee Thompson. They collaborated on plans for the future that focused on her causes.

Kate Middleton kept busy with a small dedicated team at her country home. (Will Warr)

On Sept. 8, the U.K. Sunday Times reported that Kate hoped to “potentially” join the rest of the royal family and pay tribute to fallen service members on Remembrance Sunday. This year, it falls on Nov. 10.

Kensington Palace told People magazine that Kate has already started planning her annual holiday carol concert in December. A spokesperson from the palace did not immediately respond to Fox News Digital’s request for comment.

Prince William returned to royal duties on Sept. 5. (Will Warr)

Prince William spent the summer with his wife and their three children. They primarily stayed at Anmer Hall, their country home, and Balmoral Castle in Scotland, where King Charles hosted the royal family. Kate was photographed on Aug. 25 heading to church at Crathie Kirk.

The Prince of Wales, 42, returned to royal duties on Sept. 5. It was the same week the children went back to school.