Christian replaced Simon Case as William's private secretary in March 2020 after he was poached by British Prime Minister Boris Johnson. Christian is set to join private equity group Bridgepoint as a partner.
The 31-year-old was William and Kate's communications secretary and it's believed he will remain an advisor to the couple.
It's thought Christian is responsible for protecting the Duke and Duchess of Cambridge from the fallout from Prince Harry and Meghan Markle leaving the royal family and helped keep the couple visible during the coronavirus pandemic last year.
“Whereas Simon was credited with making the Duke a statesman - Christian has really helped them to steer them through their public-facing role during the pandemic," a source has revealed to the publication. "He’s helped them to grow in confidence by gently pushing them out of their comfort zone."
Christian was initially hired as deputy communications secretary in December 2018 and provided PR support to both William and Kate and Harry and Meghan.
However, after just three months, and rumoured tensions between the couples, he was promoted to William and Kate's communications secretary.
He was promoted again after Simon left to work for Boris Johnson.
Christian was also recently named as one of the four royal aides who will give evidence in Meghan's case against Associated Newspapers after they published a letter written by the Duchess to her father, Thomas Markle.
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