Reflowing comment blocks with vim

I'm cleaning up someone else's code and working with vim. I'd like to reflow the comments so that they're formatted consistently.

For example:

    # one two three four five six seven
    # eight nine
    # ten eleven twelve thirteen fourteen
    # fifteen sixteen seventeen 
    # eighteen
    # nineteen

Would become:

    # one two three four five six seven eight nine ten eleven 
    # twelve thirteen fourteen fifteen sixteen seventeen
    # eighteen nineteen

So, a workflow that would easily uncomment the code, reflow the paragraph and then re-comment the code with the indentation preserved. If there is an existing plugin which does exactly this, that would be great.