Prince William and Princess Kate Middleton's eldest son, 12-year-old Prince George, is growing up before the world's very eyes. William, 43, and Kate, 44, brought George and his two siblings, Princess Charlotte, 10, and Prince Louis, 7, to the annual Easter Mattins service at St George's Chapel on Sunday, April 4. Kate and Charlotte twinned in beige coatdresses, while William and his sons opted for navy suits. As for George, he showed off his impressive stature as his height nearly rivaled mom Kate's on Sunday.