How to rebase and rename?

Hi!

If I have a repository with a topic branch that is published, and that I want to rebase and republish under a new name, is there an easy way of doing that?

I.e., I want to go from

      ---C---D topic-1
     /
  --A---X---X---B master

to

        ---C---D topic-1
 	  /
      /           ---C'---D' topic-2
     /           /
  --A---X---X---B master

Currently, I do something along the lines of:

  git branch topic-2 topic-1
  git rebase master topic-2

but that feels wrong as it creates the "topic-2" branch pointing the the wrong way first. Is there a way to eliminate that step?