I've just walked out of The Dorchester after interviewing Maggie Gyllenhaal. I make my way past the assorted TV crews, hovering news reporters and expectant star-gazers gathered outside the posh Park Lane hotel in central London. On the street, a girl hands me a local free-sheet: 'Holy cow! Cops Quiz Batman!' screams the headline.
Initially, I think it's just part of the military-style publicity machine surrounding the promotion of Christopher Nolan's new film. Seconds earlier I'd been handed a goodie bag by the PR people, complete with Batman T-shirt, Batman CD soundtrack, Batman diary and Batman pen ... A mock Batman newspaper was almost to be expected. But eventually I realise the story is no tongue-in-cheek ruse: the caped crusader Christian Bale has been accused of assaulting his mother and sister in his suite at this very hotel two days earlier.
It's a strange, surreal twist to the story of a film that already contains more than its fair share of shocking events. A stuntman, Conway Wickliffe, was killed during filming, while the death from an accidental prescription drugs overdose of Heath Ledger -- whose nihilistic, psychopathic Joker is essentially the main character in The Dark Knight, upstaging Bale's Batman every time he's on screen -- has ratcheted up the interest in this movie to fever pitch. So instead of it being just another summer blockbuster, there's a deep fascination, verging on the macabre, in seeing the ill-starred Australian actor's searing swansong.
The tricky part is: I know that Maggie Gyllenhaal has no desire to answer any questions about her late co-star. She practically ran out of the building during one recent interview when the subject was broached.
But any discussion about The Dark Knight that omits any mention of Heath Ledger would be like staging Hamlet without the prince. So I decide to leave that sticky question till the end ...
When I enter her hotel suite, she is sitting with one leg up on the couch, and eyeing a strawberry on her plate of fruit salad longingly, before moving in for the kill with her fork. She is wearing a classy black dress, on which run a few arty vertical stripes of dark red and green, and a pair of black open-toed flat shoes that I hesitate to call sandals.
But these are not the first things you notice -- the first things competing for your attention are those dreamy eyes and lips painted an even brighter red than that now departed strawberry.
She looks every bit as beguiling in person as she did in the photos taken of her on the red carpet the night before, where she was the belle of the ball at the European premiere of The Dark Knight in Leicester Square.
In the film, the follow-up to Batman Begins, she plays Rachel Dawes, the crusading lawyer at the centre of a tug-of-love between Batman and Gotham's crusading District Attorney, Harvey Dent (played by Aaron Eckhart).
"I tried to make the role as complex as possible," she says. "I tried to make her as full as I could. I wanted her to be a real woman with a mind, and to be as passionate about making the world a better place as the men around her."
The Dark Knight is Gyllenhaal's first superhero movie -- previous roles have included star turns as an S&M-loving office temp (Secretary) and a heroin-addicted single mother out on parole (SherryBaby). How did she find making her first big-budget film?
"I realised how big a deal it was when we shot some stuff in Coddington (south London) where they had built Gotham inside of a Zeppelin hangar. When I went in there, I thought, "Wow!"
"The other thing that's different is that something shifted in me at some point. When I was younger I didn't care who saw my movies -- and now I do. I don't want to make movies for the 10 people who feel exactly the same way about the world as I do."
A lot more than 10 people have seen The Dark Knight: it took a record-breaking $158m in the US on its opening weekend -- eight times more than its nearest rival. But if superstardom now awaits her, she is unlikely to let it go to her head.
For a start, she grew up inside the industry: her father is a director, her mother is a screenwriter, and her brother Jake has, of course, become a star himself since since he played opposite his sister in Donnie Darko.
Secondly, the 30-year-old actress has a family of her own now to look after: she lives in Park Slope, Brooklyn, with her fiancé, the actor Peter Skarsgaard (a close friend of Jake's, as it happens) and their two-year-old daughter Ramona. So how difficult does Maggie find it balancing her family life with her career?
"I made this movie when my daughter was seven months old," she answers. "I wasn't looking to work when Chris (Nolan, the director) approached me. But it ended up being a great job for a new mom because I had lots of time off. I don't think I could have done a film where I was carrying the movie -- appearing in every second of it and totally absorbed in my complicated character."
Like in SherryBaby?
"Exactly. Only now, when my daughter is almost two, do I feel like I could walk back into something like that."
Would you like to play a mothering role now that you are one? "It's interesting how since I became a mother -- and a public mother, even though I've tried very hard to keep my family out of the press -- I've been offered so many more roles as a mother. I think something changes in you, certainly, once you birth a child, once you've been through that first year, which is exhausting and incredible, but really changes you.
"When I made SherryBaby, I wasn't a mother. But I was playing someone who wasn't really a mother until the very end, so it kinda worked. I was playing a mother in World Trade Center -- and I think I probably would have been better if I'd actually had a kid. I didn't have one then."
I wonder does it help that her fiancé is also an actor? "Yes," she answers, "especially in terms of raising a child together. We both believe that parenting should be equal, although I have realised that there is something in me, in being a mom, where the baby's just gotta have you."
Did she name her daughter after the Bob Dylan song, To Ramona? "You know, we didn't, but we both really like that song. In fact, that's one of my father's favourite songs. There were a lot of things that went into her name: I'm half-Jewish, and in the Jewish religion there is a tradition of naming a child after the first letter of a relative who's died."
There have been reports that, as her fame spirals, Maggie is getting increasingly plagued by the paparazzi. How bad is it?
"It first started to get bad when I was pregnant," she says, "and they're just crazy for pregnant people. I do think of leaving the city altogether and going to live in the country. They're much better to me in the UK. They say, 'of course we won't shoot your daughter'. It's not that way in New York -- they'll tell you that ... and then shoot your daughter."
Next up for Gyllenhaal is a low-budget film called Crazy Heart alongside Jeff Bridges and Robert Duvall. But first we'll see her in a romantic comedy called Farlanders, starring Maya Rudolph and John Krasinki (Jim from the US version of The Office). It's scripted by New York literary scenester Dave Eggers and his wife.
"I play a hippy mother who's still nursing her four-year-old and is super into 'attachment parenting'," laughs Maggie, "and everyone sleeps in one big bed, and they make love in front of their children ... It was so much fun to do."
The PR girl appears to tells me I have one last question ... Delicately, I bring the subject around to Heath, and his amazing performance. As she registers the question, her eyes visibly droop, and for the first time her natural perkiness leaves her.
There is a pause. Clearly, she's already been asked this question 1,000 times. And I feel bad for being number 1,001. But at least she doesn't storm off out of the room ...
"Yeah. He was absolutely free, and really thrilling to work with. I knew he was great. But I didn't know he was SO great until I saw the movie. There's that one scene where's he upside down that I think is kind of blinding."
I mention the coincidence that both she and Jake worked opposite Heath in the two roles he'll probably be best remembered for (The Dark Knight and Brokeback Mountain).
"You know, it's a pretty small community of people, you know, of our age, making movies," she says. "I don't think it's that unusual, I guess. It's unusual that both my brother and I do it. It's also funny that my brother and my fiancé have worked together a couple of times."
With that, my time is up. She's back to her old friendly self as we say goodbye. All that's left for me to do is to pick up my Batman diary, and Batman pen, and Batman T-shirt ...
The Dark Knight opens nationwide today