LISBON, Portugal (AP) — The father of a Portuguese nurse who helped care for British Prime Minister Boris Johnson while he was in intensive care with COVID-19 says his son “got a bit of a fright” and initially worried he had done something wrong when he received an urgent call to come to the London hospital where he works.

It turned that Luis Pitarma must have done most things right. The medical team guiding Johnson's treatment wanted Pitarma to be on the team directly caring for the severely ill prime minister, the nurse's father said.

After Johnson's discharge from St. Thomas' hospital Sunday, he specifically thanked Pitarma and a colleague from New Zealand, Jenny McGee, for the skill and devotion they showed during the time he spent in the intensive care unit.

Pitarma’s parents first found out their son had the U.K leader as a patient after Johnson spent three nights in the ICU. Due to hospital rules, the nurse couldn't call to share the information until after Johnson returned to a regular ward.

“He said, 'Mum and dad, you’ll never guess who I’ve been treating -- the British prime minister!” his father, who also is named Luis, told The Associated Press.

Luis Pitarma described Johnson as “very approachable.”

“My son asked the prime minister how he should address him. He replied, ‘Call me Boris, that’s enough,’” Pitarma’s father recounted.

He said his son was picked to help care for Johnson partly because of his medical training, which includes expertise in oxygenation — a key element in COVID-19 treatment.

Pitarma, the nurse, was involved in the “most crucial” 48 hours of Johnson’s time in hospital, he told his father.

Johnson was admitted to St. Thomas’ on April 5 and moved to the ICU the next night. Officials said he received oxygen but was not put on a ventilator.

As well as earning Johnson’s public praise, Pitarma received a call from Portuguese President Marcelo Rebelo de Sousa thanking him for his role in treating the British prime minister.

Pitarma’s father, a gas appliance technician in Aveiro, a coastal city in northern Portugal, says he and his wife have since been bombarded with congratulations from family, friends and clients.

“We’re not used to this kind of thing,” he said in a Skype interview from Aveiro late Tuesday.

He said his son has been working in the U.K. as a nurse for the past six years. Pitarma's parents are “happy and proud” that his dedication has been recognized, the father said.

“To quote my son, he said he treated (Johnson) the same was as he would a rich person or a poor person. The principle is always the same: first of all, care for the patient,” he said.