Yes. You must then Discard one, however.
I actually disagree with this. I don't believe you can willingly perform an action that gives you control of two copies of the same unique character. Just as you can't band to an opponent's Captain with your Jacob to discard his Captain (assuming you have one in territory), I would say that SWS works the same way.
You do discard one of the characters if you end up controlling one by a non-optional action. If an opponent uses Samaritan Water Jar and reveals your second copy of a unique character, then you choose which to discard.
