Perhaps Middleton doesn't know who to invite now as her plus-one. After all, about three weeks ago, she finally ended, for good, her romance with Alex Loudon.
"Pippa tried to get over the split by spending last weekend with [William and Kate] at Balmoral," a source told British paper The Sun. "She and Alex split briefly in the summer, but this time it's over. They are barely speaking."
In the wake of that painful split, the insider tells Us: "From what I hear Pippa's been making a few alterations to her social calendar. It looks like she's trying to keep a low profile -- which is a bit of a change."