Princess Kate Middleton is back to brunette. The Princess of Wales stepped out with her husband, Prince William, on Monday, September 8, with her signature brown hair after surprising royal watchers with blonde locks last week. The couple took a trip to Sunningdale on Monday to celebrate the memory of Queen Elizabeth II on the third anniversary of her death. For the outing, Kate, 43, stunned in a plaid outfit with her long brown hair curled while she and William, also 43, visited the National Federation of Women's Institute, a cause the late queen supported prior to her death. (Prince Harry, for his part, was spotted leaving flowers on Elizabeth's grave amid William and Kate's outing on Monday.) While Kate and William were honoring the queen's memory, her hair was still the topic of conversation for most royal watchers. Eagle-eyed fans were quick to notice that Kate returned to her normal hair color after briefly going blonde earlier this month. Catherine, Princess of Wales listens as she visits the National Federation of Women's Institute (WI) to commemorate the three-year anniversary of the death of Queen Elizabeth II on September 8, 2025 in Sunningdale, England. Alastair Grant - WPA Pool/Getty Images Royal watchers first got a glimpse at her honey blonde hair late last month when a photo of Kate was snapped through a car window. She kicked off September by showing off the full hair transformation for an outing with William at the National History Museum in London. Does Kate Middleton Wear Hair Extensions? What Stylists Have Said Kate's hair caused quite a discussion online, with some users wondering if she got hair extensions or if the look was temporary. Princess Diana's former hairstylist Sam McKnight was among the people to slam the haters. Catherine, Princess of Wales and Prince William, Prince of Wales listen as they visit the National Federation of Women's Institute (WI) to commemorate the three-year anniversary of the death of Queen Elizabeth II on September 8, 2025 in Sunningdale, England. Alastair Grant - WPA Pool/Getty Images "I am shocked, horrified, dismayed and disgusted by all the nasty comments about the Princess of Wales today," he shared via Instagram Stories on September 4. "A woman's hair is very personal to her, it's armor, defense, confidence and so much more." Good Morning Britain's Susanna Reid Defends Kate Middleton's Blonde Hair McKnight continued, "I cannot believe how evil and lacking in any kind of empathy are the comments, the majority made apparently by other women, attacking a vulnerable other young woman, who has no choice, by dint of who she married and the role she took on, to bravely face the public." Catherine, Princess of Wales and Prince William, Prince of Wales speak to members as they visit the National Federation of Women's Institute (WI) to commemorate the three-year anniversary of the death of Queen Elizabeth II on September 8, 2025 in Sunningdale, England. Alastair Grant - WPA Pool/Getty Images Former royal butler Grand Harrold also weighed in on the "beautiful" hair change during an exclusive interview with Us Weekly. "She's been through a real s*** time. Why not enjoy? She's not afraid of doing that," Harrold said, referencing Kate's cancer battle. "It is a bit sad when people are saying, 'Oh, she's colored it because she's ill. Oh, she's color it's a wig.' I'm thinking, 'Leave her alone.'"