This being a quick post about what was said in that exchange, but apparently Henry Cavill (he of Superman) has agreed to make an appearance in Mission Impossible 6! Screenshots of the comments (before it disappears in a deluge below):
The initial tag.
Followed by the specs of what’s required.
Wait is this actually happening???
OMG YES IT IS.
And there you have it. Now we wait for the studios to announce!