In an adorable tribute to her daughter Princess Charlotte, 10, Kate wore a black bow in her hair to the concert. This is believed to be a sweet nod to Charlotte, who is often spotted wearing small bows in her hair at royal events. Prince William and Princess Kate have not been accompanied by their three children to the concert tonight.

However, Harrold said he's noticed one area in which Prince William differs quite a bit from his grandmother. "The late Queen always used to say that she put monarchy over family," he said. "Admittedly she did occasionally put family first in ways that contradict this, but she did say it often. I think William is very different."

Kate Middleton and Prince William are shielding Princess Charlotte from the potential pitfalls of being the "spare" to her brother Prince George, heir to the throne.