Kate Middleton and Prince William are experiencing a difficult period.

As the Princess of Wales continues to battle cancer, one of the couple's go-to designers Amaia Arrieta shared that she's keeping the royal family in her thoughts.

"I'm heartbroken at the moment," she told The Telegraph in an interview published May 2. "I think they are going through hell—I hope they will be back. It's really personal."

Amaia went on to explain how honored she feels to have helped dress the royals, ever since Prince George, 10, wore her brand's Amaia corduroy shorts in a 2014 Christmas photo. More recently, Princess Charlotte was pictured in her label's checked skirt in the Mother's Day photo that sparked an editing controversy.

"Dressing the royals gives me so much pride, I really do care about how they look," the designer told the outlet. "They have put the traditional and classic way of dressing children on the map."

Kate and her kids George, Charlotte and Prince Louis, 6, have remained out of the public eye for the most part ever since she underwent abdominal surgery in January. In March, the 42-year-old explained in a video that further testing showed an unspecified type of cancer had been present.

"My medical team therefore advised that I should undergo a course of preventative chemotherapy and I am now in the early stages of that treatment," she continued. "This of course came as a huge shock, and William and I have been doing everything we can to process and manage this privately for the sake of our young family."

In the meantime, William has been making occasional public appearances, including at the grand opening of James Place Newcastle on April 30, where he told well-wishers that his wife and children were doing alright.

"All doing well, thank you," William shared. "We're all doing well."

Keep reading for more tributes sent to Kate amid her health journey. 

The Beverly Hills, 90210 alum, who has herself been battling cancer for years, wrote on Instagram, "I admire your strength thru the endless onslught you've been under while going through cancer."

On March 22, 2024, Kensington Palace released a video of Kate Middleton revealing that she is undergoing treatment for cancer, which was discovered after she had abdominal surgery in January.

"Wales and the World is with you HRH Princess of Wales," Zeta-Jones, who was born in Wales and was made a Commander of the British Empire (CBE) by now-King Charles III in 2011, wrote on Instagram. "Love to you always."

The Newsroom alum, who revealed March 13 she has been battling breast cancer, commented on Kensington Palace's Instagram video of Kate, "Thank you for showing what it's like to fight with grace and determination for yourself and your family. Wishing you all the best."

"We are praying for your full & complete recovery & for strength of mind, body & spirit for you & your entire family," the Rizzoli & Isles alum commented on Kensington Palace's video of Kate. "Thank you for your beautiful spirit & courage."

The media personality, fiancée of Amazon founder Jeff Bezos, commented on the post as well, writing, "Sending love."

"My thoughts are with the Princess of Wales, Prince of Wales, the Royal Family and in particular her three children at this difficult time," he said in a statement on X. "The Princess of Wales has the love and support of the whole country as she continues her recovery. She has shown tremendous bravery with her statement today."

He added, "I know I speak for the whole country in wishing her a full and speedy recovery and look forward to seeing her back in action when she's ready."

Speaking at a press briefing following news of Kate's health battle, she said their thoughts are with the princess "and her family members and friends during this incredibly difficult time," adding, "certainly we wish her a full recovery."

"Over the years, we have climbed many mountains together," Kate's brother wrote on Instagram, alongside a childhood pic of the two, after she revealed her health diagnosis. "As a family, we will climb this one with you too."

The ninth Earl Spencer, brother of the late Princess Diana and Prince William and Prince Harry's uncle, wrote on Instagram, "Incredible poise and strength."

The Duke and Duchess of Sussex, who stepped back as senior royals in 2020 and live in California, said in a statement to NBC News, "We wish health and healing for Kate and the family and hope they are able to do so privately and in peace."

A Buckingham Palace spokesperson said the King, who shared his own cancer diagnosis in February, is "so proud of Catherine for her courage in speaking as she did."

In fact, Charles has "remained in the closest contact with his beloved daughter-in-law throughout the past weeks," the rep told NBC News, adding that both he and Camilla "will continue to offer their love and support to the whole family through this difficult time."

"You are brave," President Joe Biden's wife wrote on X, "and we love you."

"On behalf of Canadians, I’m sending my support as she undergoes treatment," he wrote on X. "We’re all wishing her a swift recovery."