And because I need to geek out some more:
The baby would be fourth in the line of succession. We currently have:
- Prince Charles
- Prince William
- Prince George
- Prince Harry
The baby would come after his/her older brother (That’s George, in bold), assuming said older brother doesn’t marry and have kids (which is always a possibility, although less so now with modern medicine and all that–it’s not quite as urgent to have a bunch of kids right off the bat to preserve the succession).