Private pages for a private Github repo

I had raised a support ticket against Github and got a response confirming the fact that ALL pages are public. I've now requested them to add a note to help.github.com/pages.

The page.github.com does mention:

Github Pages are hosted free and easily published through our site,

Without ever mentioning access control.

The GitHub page help doesn't mention any ACL either.
They are best managed in a gh-pages branch, and can be managed in their own submodule.
But again, without any restriction in term of visibility once published by GitHub.

According to GitHub Pages documentation:

All project repositories are ready to use the generator for publishing. However, please note that private repositories will publish pages that are public.

So no, at this time there is no way to create private GitHub pages from a private GitHub repository.

EDIT:

A simple workaround

A workaround for some situations that might be helpful is to simply rename the repo to something other than the GitHub pages format while you want it to be private (for example in a development phase) and when ready to make it public then correct the name. Obviously this still doesn't help if you are looking for a way to publish pages that have authentication, but if you just want to hide a GH pages project while it's in progress, this could help.

An actual Auth Wrapper for Jekyll (GitHub pages)

Alternatively, there is a project called Jekyll Auth that GitHubber @benbalter made for such use. Jekyll Auth provides a basic authentication wrapper for jekyll projects, including GitHub pages. See the repo's README for use.

Many answers are outdated (pre-Microsoft acquisition/free private repos). This one was written after the announcement of free private repos.

Github pages are not available on free private repos for individuals, as shown in the repo settings:

2020 (most basic plan is now "Team"):

NOTICE

All pages are public, even if you upgrade. Upgrading only enables the Pages feature on private repos, just like it enables other features. The Pages feature is publicly available static web hosting.