Amner, UK - Britain's Duchess Kate turned 39 on Saturday and spent the day with her husband Prince William and their three children, Prince George, Princess Charlotte, and Prince Louis, at the country estate Amner Hall.

The family stayed at the lavish country estate in the county of Norfolk over Christmas and New Year.

On Twitter, the Duchess received lots of congratulations, including some from Queen Elizabeth II (94) and her husband Philip (99).

"Wishing the Duchess of Cambridge a very happy birthday today," The Royal Family Twitter account wrote, along with a picture of Kate and the Queen.

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Prince Charles (72) and his wife Camilla (73) also sent their congrats via social media. "Happy Birthday to The Duchess of Cambridge," read their tweet.

Later that day, Kate expressed her gratitude to everyone who had thought of her through the Cambridge couple's official Twitter account: "Thank you for the kind wishes on The Duchess's birthday."

"Birthdays have been very different in recent months, and our thoughts continue to be with all those working on the front line at this hugely challenging times."

The tweet included a photo of Kate waving while wearing an elegant mask.

Kate and William traveled around the country at the beginning of December to thank essential workers for their dedication during the coronavirus pandemic.

They had to put up with criticism from the regional governments in Scotland and Wales for this. Prime Minister Boris Johnson, however, defended the royal trip.

Meanwhile, the UK has returned to a lockdown amid alarmingly high infection rates.