The Duke and Duchess of Cambridge will lose a key staff member at the end of this year.
Jason Knauf, who was employed by the couple for seven years, will stand down as Chief Executive of Prince William and Kate's Royal Foundation at the end of December 2021.
The Duke and Duchess of Cambridge said: "Jason has been an integral part of our team since 2015. We are immensely grateful for his hard work and commitment, both at The Royal Foundation and previously as our Communications Secretary.
"Since taking over as Chief Executive, Jason has driven positive change, making our vision for our charitable work and the causes that matter most to us a reality. We are sad to see him go but wish him all the very best in his future career.
"We look forward to launching the recruitment search shortly and welcoming a new Chief Executive later on this year."
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Jason said in a statement: "Working with The Duke and Duchess of Cambridge has been the privilege of my career. I will always be grateful for the opportunity I have had to support their leadership in the UK and internationally.
"The months ahead will be the busiest time in the Foundation's history with the first awards for The Earthshot Prize and more progress on our early childhood work. We have a lot to do with our amazing team and all of our partners."
Jason first joined the royal household in 2015
The American PR guru first joined the royal household in 2015, first as a communications secretary to the Cambridges and then as their senior advisor.
He previously worked at the Royal Bank of Scotland and was also once an adviser to the former New Zealand Prime Minister Helen Clark.
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William and Kate said they are sad to see Jason leave his post
In his time as Chief Executive, Jason has overseen the development and launch of the Foundation's most ambitious programme to date – The Earthshot Prize – as well as the continued development of The Duchess' pioneering work on early childhood.
He has helped steer the Foundation's response to COVID-19, establishing a response fund which saw £1.8 million granted to causes supporting frontline workers and the mental health needs of the nation in August 2019.
In a statement from the Royal Foundation, it says Jason will remain in post until the end of 2021 before a planned international relocation that has necessitated his decision to stand down.
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