James Cameron + water: it's a recurring motif. If he made the life story of Rommel, he'd figure out a way to set the North African campaign at the bottom of the Pacific. AP reports:

So she has no idea if she'll be in it, but knows it will be beautiful? Probably a good guess; it has to be the loveliest world imaginable, so we can boo-hiss the mean guys who want to drill for liquid unobtanium, or whatever the plot's about this time. Maybe it will have sexy fish people.