First doctors, now bunnies.

A valuable giant rabbit that was “fit as a fiddle” — and destined to be the world’s biggest bunny — mysteriously died while flying United Airlines UAL, -3.61% , a report says.

“Something very strange has happened and I want to know what,” fumed breeder Annette Edwards, 65, of the U.K.

“I’ve sent rabbits all around the world and nothing like this has happened before,” she told The Sun. “The client who bought Simon is very famous. He’s upset.”

Edwards had been flying with the three-foot Continental Giant rabbit, dubbed Simon, out of Heathrow Airport to his new celebrity owner in the U.S. when he inexplicably kicked the bucket.

“Simon had a vet’s check-up three hours before the flight and was fit as a fiddle,” she explained.

The prized pet had been stored in the cargo section of the Boeing 767, which is where United Airlines crew members found his lifeless body upon landing at Chicago’s O’Hare International Airport — the same place the infamous David Dao incident occurred.

United Airlines passenger violently removed from flight

On April 9, Dao was forcibly removed from his seat and battered by airport police in the attempt to make room for United staff. The doctor’s attorney later claimed that the incident left him with a concussion, a broken nose and two missing front teeth.

Read:America’s least favorite airline is NOT United Airlines

Airline sources told The Sun that United was scrambling to find out what happened to Simon following his death — and that they now fear another potential PR disaster could be on the horizon.

“After the viral video no-one wanted responsibility for killing what was to be the world’s biggest rabbit,” a source said of the scandal-plagued airline.

Edwards — a great-grandmother and mother of ten who previously made headlines in the U.K. after she tried to use plastic surgery to transform herself into a real-life Jessica Rabbit from “Who Killed Roger Rabbit” — claimed Simon was on track to become the world’s biggest bunny before he died. His father, Darius, is the current record holder at 4-feet, 4 inches.

United told The Sun that they were looking into Simon’s death.

“We are reviewing this matter,” the airline said.

Giant rabbits are known to cost more than $6,000 a month to keep, the Sun reports.

According to the outlet, international flight regulations require that rabbits and other animals be transported in an area of the plane’s hold that is both heated and pressurized.

They are reportedly kept in cages with food and water. The price to store a pet can sometimes be more than $2,500 in some cases.

United Airlines normally allows rabbits to travel in the cabin with their owners during domestic flights in the U.S, but not while flying internationally.

This story originally appeared at NYPost.com