Looking at information I have collected from various different sites, it would seem as though BB USA has 2 sets of twins - they are Drew & Ben and Adria & Natalie.
Drew and Ben are pictured
HERE (Identical, apart from the fact that Drew has moles on his chest and Ben hasn't)
Adria & Natalie are pictured
HERE (Adria has a mole on the right side of her face by her nose. Natalie has a mole under her right eye.)
I believe that viewers have been told about Adria and Natalie, but it is suspected that Drews twin brother Ben is also taking part, as an aquaintance of his says that he has gone missing.
From what I can understand, it would seem as though the twins swap places every few days, whilst the other one stays in a secret room the other side of the Diary Room. They have about 15 minutes in the Diary Room together where they can swap clothes and stories and apparently if they can last up to the half way point without the others finding out, then they will both be allowed in the house to compete for the final prize money.
