It was a perfectly believable story, as the the actors were both newly single; they were filming Live By Night together; and what red-blooded male wouldn't want to bang Sienna Miller?
Now, however, things are going in a direction that we never could have predicted.
What we thought was nothing more than a convenient on-set rebound bang appears to be shaping up into an actual relationship!
Yes, SiBenna might actually be a thing, as several photos of Ben and Sienna holding hands have emerged online.
Sure, they may have been in character, or Sienna might have been feeling the smooth, un-calloused hands of a dude who's been famous since early 20s, but as far as we're concerned hand holding = relationship.
It's an odd development for a number of reasons.
For one thing, Ben has been doing his best to avoid negative publicity throughout his split from Jennifer Garner.
As far as we can tell he paid Christine Ouzounian to disappear off the face of the Earth!
Now just a few months before the release of Batman v Superman, he's gonna let himself be caught canoodling with a woman a decade younger than his wife?!
And as for Sienna, is she really gonna let herself get mixed up with another nanny-banger? Didn't she learn her lesson from Jude Law?