We've been really clamoring for some new "The Mortal Instruments" casting news lately, and while we still don't have a Simon, voila! Our Isabelle Lightwood is now in the house!

Series author Cassandra Clare spilled the beans yesterday on her blog that French "The Borgias" actress Jemima West will portray the vixen shadowhuntress for the film, joining the already in-place castmembers Jamie Campbell Bower and Lily Collins.

"She's beautiful (like whoa) and really talented," Clare wrote about West. "You can see her as Vittoria on 'The Borgias' right now. She had a lot of Izzy's toughness and directness in her audition. I like her."

Clare also said that another actor has been formally wrangled in for the part of Izzy's powerful older brother, Alec Lightwood, and she was going to spill who that was too but then came back with the news, "I can't tell you who Alec is because — well, I don't entirely know why, but it has to do with his schedule, and telling could get a bunch of people shot."  Well, we certainly don't want that.

Clare did, however, manage to sneak in a tease that the actor in question is British — not Nicholas Hoult — and he "may well be a lot more known to you" and "has dark hair." Immediately, our minds went to "Gossip Girl" star Ed Westwick, who narrated the audiobooks. We're not alone in that, and when someone on Twitter asked Clare whether Westwick was the man for Alec, she didn't exactly deny it!