Nearly three months after announcing her cancer diagnosis, Kate Middleton broke her silence.

“Being your Colonel remains a great honour, and I am very sorry that I’m unable to take the salute at this year’s Colonel’s Review,” she wrote in a letter to the Irish Guards, who held an annual dress rehearsal on the Mall in London a week before the monarch’s ceremonial birthday celebration on June 15. “I do hope that I am able to represent you all once again very soon.”

And while Kate made her first public appearance in six months at Trooping the Colour, the bigger news was her rumored reasons for missing the rehearsal a week earlier on June 8.

According to internet sleuths, the Princess of Wales was recently spotted nearly 5,000 miles away in Houston.

“There are multiple witnesses who claim to have seen her in Texas,” a source exclusively tells Life & Style. “It’s believed she’s flying back and forth for secret cancer treatment there.”

The sightings are very specific. On June 9, one Reddit user reported that they were “visiting friends at the St. Regis and they spoke about her being at the hotel,” while another claimed to have heard from a staffer at the University of Texas MD Anderson Cancer Center that Kate, 42, was there.

Yet another wrote that they spotted her “hiking and laughing with her bodyguard” on a trail near the hospital.

She wouldn’t be their first high-profile patient. Terry Bradshaw, Kelly Preston and Eddie Van Halen are among the celebrities who have been treated at MD Anderson, which is frequently named the best cancer center in the world and specializes in the deadliest forms of breast and ovarian cancer, along with lung and prostate cancer, melanoma and leukemia. (Kate has not disclosed what type of cancer she has.)

Prince George of Wales, Prince William, Prince of Wales, Prince Louis of Wales, Catherine, Princess of Wales and Princess Charlotte of Wales
Chris Jackson/Getty Images

With locals buzzing, the Houston Chronicle reached out for comment. “A rumor that Kate is being treated at MD Anderson in Houston is false, according to a Kensington Palace representative,” they reported on June 10. But the source points out, “That doesn’t mean she couldn’t have been there before, or that she wouldn’t see other specialists in America. Obviously, it would not be something they would want to confirm, for multiple reasons.”

Those include security, privacy — and public image. The idea of a member of the royal family seeking treatment from anywhere other than the National Health Service “would be a bad look,” says the source. “It would suggest that the care that ‘regular’ Britons get isn’t good enough for the princess, who is wealthy enough to afford better doctors. But the truth is, [Prince] William will pay any amount of money to make sure she gets better.”

Whatever she’s doing seems to be working. “It’s been brutal, but Kate has turned a corner,” says the source. After all, Kate appeared in good spirits as she celebrated father-in-law King Charles III, who is fighting prostate cancer, at the Horse Guards Parade in London. She was joined by husband Prince William and their three children Prince George, 10, Princess Charlotte, 9, and Prince Louis, 6.

Adds the insider, “She’s truly hoping to reassure everyone soon that she’s in the clear.”