Prince William and Duchess Kate joined their family — including pregnant Meghan — to celebrate Prince Charles’ 70th birthday.

What a lucky guy! On

Nov. 13, the royal family released an official portrait in honor of

Prince Charles’ 70th birthday. (It was taken in midSeptember, says a source, before anyone knew Duchess Meghan was pregnant!) The next night, at a birthday bash, Charles’ mother,

Queen Elizabeth II, gave a touching speech about her son, saying that watching him grow up has been like “planting a tree and being able to watch it grow.” The 92-year-old added that when her own mother saw her turn 70, she called it “exactly the age when the number of candles on your cake finally exceeds the amount of breath you have to blow them out.” Guests at the exclusive London soirée included Duchess Camilla, newlyweds Princess Eugenie and Jack Brooksbank, Prince William and Duchess Kate,

and Prince Harry and Duchess Meghan (right). Meghan, 37, who’s about 20 weeks pregnant, “is doing very well,” a source tells Us. “Pregnancy agrees with her!”

If the littlest royals — Prince Louis, 6 months, Princess Charlotte, 3, and Prince George, 5 — look happy, it may be because their nanny, Maria, “was making silly faces” at them,says a source.