King Edward VII's hospital in London acknowledged that an Australian radio station made a hoax call to the hospital in the early hours Tuesday - and the hospital fell for it.
The 30-year-old Duchess of Cambridge is pregnant and is being treated at the hospital for severe morning sickness.
A woman using the often-mimicked voice of the monarch asked after the duchess' health - and was told that Kate "hasn't had any retching with me and she's been sleeping on and off."
"She's sleeping at the moment and she has had an uneventful night. She's been given some fluids. She's stable at the moment," the kindly nurse informed the supposed queen and Prince Charles on the station's recording. A dog yaps in the background while the "queen" and her son talk about traveling to the hospital to check in on the patient.
"I would suggest that any time after 9 o'clock will be suitable to visit," the nurse said. "We'll be getting her freshened up."
The duchess is married to the queen's grandson, Prince William.
The hospital says the call had been transferred to a ward and the conversation was held with one of its nursing staff. Its telephone protocols are being reviewed, the hospital said in a statement.
The Australian station 2DayFM has placed the recording of the conversation on its website.
The duchess is spending her third day in the hospital while being treated for acute morning sickness.
William visited his wife at the hospital for several hours on Tuesday, while media from around the world camped outside, seeking news on the royal pregnancy. Officials from St. James's Palace have said the duchess was not yet 12 weeks pregnant.