I heard this on the radio today and it caught me by surprise. Apparantly they're still in talks, hopefully not in any major roles, but if they do actually appear in the film they'll make Bond history by being the first set of twin bond girls.
http://www.stuff.co.nz/4064257a1870.html
Other actors rumored for this one are Sienna Miller, Goran Visjinic as the baddie, and Abbie Cornish.