Kate, Harry and William often look like the Three Musketeers together, but William can't be there all the time!
Enter Prince Harry. His apartment is right by the Duke and Duchess of Cambridge's cottage at Kensington Palace, and he reportedly told Kate that she can call him if she needs anything.
Sources also say that Harry took a few days off work late last week in case the baby came, so he could be at Kate and Will's side when he becomes an uncle.
We think the Kate, Harry and William friendship trifecta is the sweetest thing. Are you buddies with your in-laws, if you have them?