Kate Middleton is such a devoted mom!

Royal sources have exclusively revealed to Closer Weekly that the Duchess of Cambridge is preparing to become queen in 2017 — but she is refusing to give up quality time with her two kids while taking on the new role.

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"These precious days can never be brought back. [Princess Diana] knew that too," Paul Burrell, Diana's former butler, told Closer in the magazine's latest issue, on newsstands now.

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Kate, William, George and Charlotte in September 2016.

Kate shares son Prince George, 3, and daughter Princess Charlotte, 1, with husband Prince William, 34. The royal couple — who married in April 2011 — welcomed George in July 2013 and Charlotte in May 2015.

In order for the 35-year-old princess to begin preparing to one day take over as queen, Kate and her family are planning to relocate to London this year to live in the royal family's Kensington Palace residence.

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Kate and William have been raising their little ones in their Norfolk, England country home, Amner Hall, for the past three years.

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Kate and Queen Elizabeth in June 2012.

“In London, Kate will be able to get to official business more easily than when she was living at Anmer Hall in Norfolk,” an insider explained to Closer Weekly. “She has always made it clear that family comes first, but now her diary will also be full of official events.”

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William and his wife have already been increasing their royal outings in recent months. In 2016, Kate appeared at 140 royal engagements while William went to 188 events.

The couple and their children also traveled to Canada for their first royal tour as a family-of-four last fall. This was Charlotte's first overseas trip. Her older brother, George, embarked on his first royal tour in April 2014 for a three-week visit to Australia and New Zealand with his parents.

Click through the gallery below to see more adorable photos of Kate, George and Charlotte!