(LONDON) -- The hospital where Kate Middleton is battling acute nausea fell for a prank call from an Australian radio show, revealing to the royal impersonators that Kate is "quite stable" and hasn't "had any retching."
Wednesday is the pregnant duchess's third day at London's King Edward VII Hospital, where she is undergoing treatment for hyperemesis gravidarum -- severe or debilitating nausea and vomiting. Prince William and her sister Pippa Middleton both visited her in the hospital Wednesday.
The hospital inadvertently revealed new details about Kate's condition when Australian DJ's Mel Greig and Michael Christian called in and pretended to be Queen Elizabeth II and Prince Charles, complete with exaggerated accents. They even enlisted two co-workers to bark like the queen's corgis.
The queen impersonator asked for her granddaughter and was promptly transferred to another hospital employee.
"I'm just after my granddaughter, Kate. I want to see how her little tummy bug is going," the radio host said, suppressing laughter.
"She's sleeping at the moment, and she has had an uneventful night and sleep is good for her," the nurse said. "She's been getting some fluids to rehydrate her because she was quite dehydrated when she came in, but she's stable at the moment."
The fake royals went on to ask when would be a good time to visit and were told that "anytime after 9 o'clock would be suitable."
"She's quite stable at the moment. She hasn't had any retching ... since I've been on duty. And she has been sleeping on and off. I think it's difficult sleeping in a strange bed as well," the nurse said with a laugh.
The hospital confirmed Wednesday that the call happened early Tuesday morning.
"The call was transferred through to a ward, and a short conversation was held with one of the nursing staff," the hospital said in a statement. "King Edward VII's Hospital deeply regrets this incident."
"This was a foolish prank call that we all deplore," John Lofthouse, the hospital's chief executive, said in the statement. "We take patient confidentiality extremely seriously, and we are now reviewing our telephone protocols."
The radio station has since apologized for the prank call.
Hyperemesis gravidarum, or acute nausea, is usually diagnosed about nine weeks into a pregnancy, and in most cases resolves itself by 16 or 20 weeks, according to Dr. Ashley Roman, a professor and obstetrician-gynecologist at New York University Langone Medical Center. In rare cases, it can last the whole pregnancy.
The Sun reports that Prince Harry sent Kate an email from his post at Camp Bastion in Afghanistan, telling her to "Get well soon, Sis."
Kate will be in the hospital for “several days," and will then require a "period of rest," Clarence House said Monday.
Copyright 2012 ABC News Radio