The Princess of Wales enjoyed a low-key birthday lunch with her mother, Carole Middleton, and sister, Pippa Matthews, at a local French bistro in Berkshire.
HELLO! understands Kate dined at The Funghi Club in Hungerford last Friday to mark turning 44.
A Facebook post from the bistro described the royal as "utterly charming, gracious and radiant".
The full post read: "Every now and then something happens that sends a little fizz of excitement through the whole place and this week delivered a corker. Last Friday, in our teeny Hungerford Bistro, we had the enormous pleasure of welcoming a rather extraordinary guest.
"We can already hear the chorus from Newbury: 'Go on then… who was it?' Well - none other than the Princess of Wales herself, Berkshire's very own Kate Middleton, celebrating her 44th birthday, joined by her mother Carole and sister Pippa. Right here in Hungerford.
"No photos to share (you'll understand why), but the entire team on duty reported the same thing: she was utterly charming, gracious and every bit as radiant in person as you'd imagine. The jungle drums of Hungerford didn't stop beating until well into Saturday. A little moment of magic for our small bistro — and one we won't forget in a hurry. Happy Birthday."
The restaurant, which also has a branch in Marlborough, offers an array of French dishes, including Beef Bourguignon, escargots (snails) in a parsley and garlic butter, souffles, crepes and cheese and meat platters on it’s affordable a la menu, all of which appears to be under £22.
As well as a selection of wines, beers and soft drinks, the menu also offers cocktails, including a French 75, which is made with gin, lemon juice, simple syrup and topped with Champagne.
Its website states: "Our all-day French inspired bistros have been created to evoke a relaxed and carefree feeling, with no strict rules between starters, mains, or desserts."
It's no surprise that the Princess of Wales opted to support a local business on her special day on 9 January, as she and Prince William have been known to pop into local pubs and restaurants near their Norfolk abode, Anmer Hall.
Breaking tradition on her birthday
The day before her birthday, Kate joined her husband at Charing Cross Hospital in west London to offer support to staff amid the challenging winter period, which has seen record levels of flu cases.
In a break from tradition, Kensington Palace shared a video on her birthday instead of a new portrait of the Princess talking about the healing power of nature as she concluded her Mother Nature film series she launched last year.
The footage showed Kate wrapped up in a green trench coat and a Baker Boy cap as she enjoyed a stroll through the Berkshire countryside.
In a voiceover, she said: "Even in the coldest, darkest season, winter has a way of bringing us stillness, patience and quiet consideration. Where the stream slows just enough for us to see our own reflection.
"To discover the deepest parts of ourselves. Alongside the whispers in the pulse of every living thing. I find myself reflecting on how deeply grateful I am.
"For the rivers within us flow with ease, fears washed away, cleanse and purify. Come to peace with our tears and discover what it means to be alive.
"To be at one with nature; a quiet teacher and a soft voice that guides. In memory. Helping us to heal."