The raven-haired beauty will play "a glamorous, enigmatic character" named Severine opposite Daniel Craig, who's confirmed to reprise his role for the third time.
Marlohe -- a French model and actress with mostly French television credits on her resume so far -- sizzled at Thursday's press conference in a red-hot, skin-tight gown designed by Antonio Berardi. "It's great," Marlohe told the Daily Mail of the frock. "I feel very sexy in it."
Another stunner to sizzle alongside Craig, 43, is British actress Naomie Harris, who will play a field agent named "Eve."
At the big reveal -- Craig, Marlohe and Harris joined costars Javier Bardem, Dame Judi Dench, Ralph Fiennes, Albert Finney and Ben Whishaw -- director Sam Mendes said that Skyfall will "not connect" with the plots of the two most recent Bond films, Quantum of Solace and Casino Royale.
"Bond's loyalty to M [Dench] is tested as her past comes back to haunt her. As M16 comes under attack, 007 must track down and destroy the threat, no matter how personal the cost," said the film's press release.