William made the comments on a call with a consultant at Belfast hospital, it was one of a series of telephone and video calls to NHS staff across the country and in all departments since the start of the year.
On the call with Dr Thelma Craig, a respiratory consultant at the Mater Hospital, William said: "I just want to say on behalf of everyone what a fantastic job you’ve done. You’ve all held it together and been absolutely wonderful people.
"It’s been a real team effort but we’re all very proud of you. The NHS has gone from already being much loved to probably the most admired organisation around.
"Thank you so much for all your hard work."
Kensington Palace said that since the start of the year the duke had spoken to more than 300 staff and volunteers spanning the breadth of the NHS workforce across the UK.
William's office said he wanted to check in on the wellbeing of all those supporting the NHS, and to thank them for the vital part they have played during the crisis.
Last month, William had an emotional call with nurse Jenny Manson who formed a bubble with the family of a terminally ill girl to protect them from Covid-19 last summer.
Ms Manson, a community children’s nurse from Kirkcudbright in Dumfries and Galloway, told the duke how she had cared for nine-year-old Holly Clarke at her home.
It allowed Holly's parents Richard and Stevie Clarke, her twin sister Becca and older sister Emily to spend their last precious months with her before her death in October.
The family nominated her in the Nurse of Year category of the Scottish Health Awards and she won, receiving her honour late last year.
The 54-year-old, a single mother herself to 16-year-old twin daughters, worked at the family’s home from May last year, to protect them from the risk of catching the virus.
Speaking about her call with William she said: "I’m just a little nurse who works in Scotland but for the duke to actually want to take time to talk to me it felt I was so privileged. I felt like my job and the role of the NHS was really being acknowledged.
"He was unbelievably genuine and sincere."
She added: "He said as a father it made him feel quite emotional, the conversation we were having.
"He talked to me about when he was working as a helicopter pilot and how when he went to a child who had had a trauma or an accident that that used to be called really sad. He spoke about that a lot and he was just so sincere.”
The nurse went on to say: "He was really interested to know how I managed that situation and I told him that what I did was that I became part of that family’s bubble.
"I worked with them constantly really so it stopped other professionals having to go into the house, which the family really, really appreciated.”
In February, William spoke to Shamraze Zeb a practice manager at Black Country and West Birmingham Clinical Commissioning Group, who has been helping to manage the vaccine rollout across a Primary Care Network of nine GP practices.
The 41-year-old told the duke how the team had set up pop-up clinics at local Mosques and Gurdwaras to tackle the problem of vaccine hesitancy in the area.
The practice manager said: "He asked me about the uptake in the mosque and how it went and I explained to him that we had patients that had declined previously, but they turned up at the mosque just because of public trust."
He added: "We had a conversation about how he was aware of the vaccine hesitancy, but he was saying that the more factual information we can get out into the media and into different channels that will help the cause and he said that it was fantastic that me and my team are going out and doing these initiatives to increase the uptake."
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