Kate Middleton Worries Loved Ones By Working Nonstop During Her Pregnancy

At six months pregnant, most women would be seizing every possible opportunity to kick up their feet and unwind.

Then there’s Kate Middleton. Although the Duchess of Cambridge is already entering her third trimester and busily prepping for Baby No. 2 – while simultaneously caring for an energetic toddler, 18-month-old son Prince George – she’s showing no signs of slowing down her hectic schedule.

Case in point: On Jan. 19, the 33-year-old donned a pair of sky-high heels and spent the chilly London day attending three separate public engagements in the Kensington area.

A pregnant Kate at an appearance on Jan. 19, 2015.

“Kate has never been so busy,” an insider tells ‘Closer.’ “She wants to be an example to other working mothers.”

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Mission accomplished – but those close to Kate, including her husband of almost four years, Prince William, 32, are concerned that she’s trying to do too much.

Kate with William and George in April 2014.

“William just wants her to be healthy,” says the insider. ‘When she’s rushing around, she ends up burning too many calories rather than conserving her energy.”

Indeed, during a recent shopping outing, Kate looked noticeably thin – “she’s tiny and barely put on any weight,” says the insider – and uncharacteristically haggard, even sporting a few telltale gray hairs.

To read the full story on Kate, pick up the new issue of ‘Closer Weekly,’ on newsstands now!