The sixth edition of CBS' Big Brother, premiering July 7, will up the ante by offering the chance for a doubled grand prize. But to cop the total million, the winner will have to keep a lid on the show's new twist: that each player, from the moment they enter the house, is secretly in alliance with another. (And, stay with us here, each pair of partners thinks they are the only ones in cahoots.) If one of the twosomes makes it intact to the final round of voting, the winner gets a mil, and his/her buddy gets $250,000. "So it's in their best interest to keep [the alliance] a secret," executive producer Allison Grodner tells Variety. Blab, and the payoff is reduced to $500K/$50K.