I guess it's been rumored for some time now, but Nicola Peltz has been confirmed as GIRL in Transformers 4 via twitter:
There may be more GIRLS than just this one GIRL, but I'm pretty sure she's the main GIRL. In other words, there may be a kid or two in this film, but this is the one you're supposed to want to have sex with in the back of a Transformer. Actually, I think she's playing Mark Walhberg's daughter, so maybe she's a bit of both. (I'm a really bad person)
You may know Peltz as Katara from The Last Airbender (the live-action movie, not the animated adaptation) (I'm a really bad person). She's also on Bates Motel. Unlike a lot of ladies in Michael Bay movies, she's both young and beautiful, which means I have a hard time telling her apart from a lot of other young pretty ladies. Lack of distinguishing features will at least make her of a piece with the rest of Michael Bay's Transformers Universe.
Today also brings news that Transformers 4 will be shot in 3D. I would deliver that tidbit to your elderly family members cautiously, as the surprise may send them into cardiac arrest.