This week we got an adorable and relatively rare glimpse of Princess Charlotte, who turns seven years old exactly one month from today. (Princess Charlotte attended a service honoring the life of her great-grandfather Prince Philip, who died last April at age 99, along with her brother Prince George and her parents, the Duke and Duchess of Cambridge.)

And while we know that Charlotte uses her grandmother Princess Diana's first name as one of her two middle names, Charlotte may have more in common than just sharing a name with "Grandma Diana." Body language expert Judy James told the Daily Express that both Charlotte and her late grandmother are shy at first, but once they get to know each other, they share a cheerful and bright personality.

"Charlotte had the inspiring appearance of the queen when she was little, but she displayed body language traits similar to Princess Diana's," James said.

As they exited the car, Charlotte held her mother Kate's hand and George held William's. At one point, according to the Daily Express, Kate said to her only daughter, "You can smile," and together they walked through Westminster Abbey. Charlotte smiled for the camera.

Once inside the abbey, George and Charlotte were introduced to the Archbishop of Canterbury and several other bishops and clergy. The magazine reported that Charlotte was urged and encouraged by Kate when meeting new people.

During the service, Kate said "shhh" to Charlotte, who waved enthusiastically with her cousin Mia Tindall and engaged in adorable exchanges with her cousin Princess Beatrice.

Philip's service was "probably the first big test for George and Charlotte in terms of proper royal behavior in a formal setting watched by cameras around the world," James said.

George exchanged words and laughter with his sister during the service, but thanks to Kate's guidance, James said, Charlotte was able to behave.

"Kate's little whispers to her daughter seemed to keep her well behaved, but walking past the rows of Zara and Peter Phillips' daughters, who were relaxed, chatting, and laughing, must have been one of the biggest challenges of her royal life so far." James said. 'Little Mia was waving excitedly as her friends walked past. Charlotte must have been learning for the first time about the limitations of royal protocol."

Charlotte is much like her great-grandmother, the queen, but her nascent personality is really more like the grandmother she never knew. She is shy, but when she opens up, she is surprisingly fun, confident, and lively.