The third case was confirmed by the Department for Health on Tuesday afternoon, after two people fell ill with the virus in York last week.
Images which emerged from overnight appeared to show an ambulance and paramedics in hazmat suits on Hull Road in York, however the local authority has confirmed this patient was tested negative for the virus.
York City Council's Director for Public Health Sharon Stoltz said: "The test on the person from the Hull Road area in York recently reported in the media has been confirmed as negative for the virus."
England's Chief Medical Officer Professor Chris Whitty said the third confirmed case was being transferred to on of the UK's four infectious diseases centres for treatment.
The two patients taken ill in York last week are still being treated at the Royal Victoria Infirmary in Newcastle upon Tyne.
In a statement, Prof Whitty said: "A further patient has tested positive for coronavirus, bringing the total number of cases in the UK to three.
"The individual did not acquire this in the UK.
"The patient is being transferred to a specialist NHS centre, and we are using robust infection control measures to prevent any possible further spread of the virus.
"The NHS is well prepared to manage these cases and we are now working quickly to identify any contacts the patient has had."
Ms Stoltz added: "The risk to residents and visitors in York remains low and the City is still a safe place to live and work in and visit."