London hospital officials say a nurse who mistakenly accepted a prank phone call for Catherine, the Duchess of Cambridge this week has been found dead.

Authorities at the King Edward VII Hospital on Friday confirmed the death of Jacintha Saldanha and said she had been the first recipient of the prank call for the Duchess, who is pregnant. British authorities say they are investigating the death as “unexplained.”

St. James's Palace issued a statement on behalf of Prince William and the Duchess expressing sadness at the news.

Two Australian radio announcers called the hospital on Tuesday pretending to be Britain's Queen Elizabeth and her son, Prince Charles, seeking information about the condition of the mother-to-be. The nurse apparently passed on their call to the maternity ward without recognizing the joke.

The hospital and the Australian radio station each made apologies later for the incident, and the hospital has launched an investigation.

Prince William's wife, Catherine, known officially as the Duchess of Cambridge, was admitted to the hospital Monday for treatment of severe morning sickness. Her admittance forced the palace to announce that she is pregnant with her first child.

She was released from the hospital on Thursday, smiling and carrying flowers, and is expected to spend some time recuperating at the couple's London home.