Princess of Wales Kate Middleton returns to work in Windsor

Reports suggest that she is pregnant with her fourth child

Prince William and Kate have informed King Charles about the good news

The late Queen Elizabeth was also aware of the pregnancy

Kate has returned to royal duties after spending time with family

Her last royal duty was on October 15

She received the Chief Executive of the Royal Foundation at Windsor Castle

Kate and Prince William have three children together: Prince George, Princess Charlotte, and Prince Louis

Kate is a patron of the Royal Foundation of the Prince and Princess of Wales.