Julie Delpy: Julie, madly, deeply

She's Hollywood's golden girl once more. Julie Delpy tells Charlotte O'Sullivan about the light and shade in her life

Julie Delpy wants pasta for lunch - without butter. The 34-year-old French actress holds her hands together as if in prayer. "Olive oil, please. Everything olive oil!" She's all of a flutter - her wavy golden hair; her grey-black gossamer skirt; her veal-pale, imploring hands. An airy-fairy vision of loveliness, only her respectable shoes - round-toed with a clunky heel - appear capable of keeping her tethered to the ground.

Julie Delpy wants pasta for lunch - without butter. The 34-year-old French actress holds her hands together as if in prayer. "Olive oil, please. Everything olive oil!" She's all of a flutter - her wavy golden hair; her grey-black gossamer skirt; her veal-pale, imploring hands. An airy-fairy vision of loveliness, only her respectable shoes - round-toed with a clunky heel - appear capable of keeping her tethered to the ground.

A decade back, Delpy's light touch was all the rage, her casual intensity shown off to particular advantage in Three Colours: White (she was the porcelain, money-grabbing wife) and Richard Linklater's Before Sunrise (in which she and Ethan Hawke's Celine and Jesse walk and talk through Vienna as love blooms). The films that followed, however, were a let-down. Under-written parts in An American Werewolf in Paris and LA Without A Map made her appear somehow insubstantial. Worse still (as far as Hollywood was concerned) she began to look strangely worn - gaunt and almost antiquated; a Miss Havisham among the latest crop of Estellas. Watching her on television as a needy hysteric in ER, or a put-upon maid in the 2002 Europudding Villa des roses, one could only conclude that Delpy's several seconds of fame were up.

And then along came Before Sunset ( see Anthony Quinn's review, page six), a follow-up to Before Sunrise, which reunites the now thirtysomething pair in Paris, where Celine lives. Delpy wrote most of her own lines, via an e-mail exchange with Linklater and Hawke, and the result is a fabulously complex character (think Phoebe in Friends, as seen through the narrowed eyes of Eric Rohmer). The actress looks gorgeously sun-dappled; the film itself, released in the States last month, was a critical and commercial success. Having lived in LA for years, Delpy is suddenly "hot" all over again. Even long-dreamed of directing projects look set to take off.

Sitting before me now, she admits the irony of her position. In her sing-song French-Californian twang, she explains that the film is all about connection - about wondering if the person who seems so significant to you even remembers your name. "But when you become a famous person, you become that person for much more persons than you think you do. I meet a guy who I've met, like, ten times and it's been so meaningful to him, and I never remember him!"

She flashes a smile, revealing the world's smallest, pearliest teeth. "And I hate myself, but I can't help it!"

Her parents have a cameo in Before Sunset, as a couple who live in Celine's block. I ask Delpy if she worried about exposing her "real" life in this way, and her mouth tightens. "But they don't play my parents. It's not a reality show."

I make a mental note: must avoid interviewing fey actresses in future. Meanwhile, Delpy's brow has furrowed: "Actually, at one point, we did think about having this funny thing. That what Jesse doesn't know is that Celine lives in the flat above her parents! Which is every man's nightmare, of course. I wrote a whole script about that once."

I point out that, in the movies, people who live that close to Mommy or Daddy tend to be crazy (see Psycho for details). Delpy makes a face. "The madness, yes...", then says in a flushed rush, "Well, I do live upstairs from my parents! And I have to say it is the most disturbing thing in the world!"

Clearly, Before Sunset is something of a "reality show". And having acknowledged this, Delpy herself seems transformed.

She leans forward confidingly: "My mum convinced me to buy the studio upstairs from them, for when I come to Paris. But I swear to God, after two weeks, it becomes such hell, that I end up staying at friends!" She laughs (a deep, Father Christmas chuckle, entirely at odds with her slight frame). "They hear me when I get home, and what time I get home. I'm like - 'I'm 34, I can't do that anymore!' "

It doesn't help that she's an only child. "My mum is so possessive of me!" she continues. "Yes, I'm away a lot. But there's this guilt trip my mother plays on me. [She adopts a wheedling voice] 'You're so far away, you left home when you were 18, I never get a chance to spend time with you.' And she sucks me in, but I can't stand it!

"In fact, I'm about to buy another place. I've got to love them from afar!"

At this point, the PR slips into the room with Delpy's food - chicken and salad, plus a big bowl of salad. Apologising at least four times, Delpy tucks in. Astonishingly, she still manages to keep on talking.

Her mother "doesn't understand quiet". Her father, by contrast, is very quiet (her mother's family, apparently, hate him: "Because he's a pussy!") Delpy adds that she's always been drawn to shy men. In fact, she says, clearing her throat, she's currently seeing someone and he is "extremely shy".

I remind her of something she once said, which was that - in a romantic sense - she'd never made the first move in her whole life and that, as a result, she didn't think she'd ever been with someone she really loved, because the people she really cared for, she didn't have the nerve to go after.

So who made the first move in this case?

She snorts. "Actually, I had to. Because otherwise we'd still be politely shaking hands. And I was pushed by friends. It took a lot - it was very hard for me, but I did it! I decided I wanted to really choose someone." She bites her lip. "And not make mistakes anymore."

"But you know," she says quickly, "it's OK. I'm very happy in my love-life. I've always been loved. I've been very lucky in love. It's funny to say that, because I'm not married and I don't have a kid. But I've been loved a tremendous amount by people."

I don't doubt it, I say, a little puzzled. The problem, surely, was more that she couldn't love back.

"But no. I could love back. And I was very loved. OK. Maybe one or two guys, it didn't last more than a week. But otherwise..."

I have one last go: I'm not questioning how much she was loved. She said she had trouble loving.

"That was my character saying that!" No, I say, this was in real life. "Oh!" she exclaims brightly. "You know what it is? I keep changing all the time. Changing my mind. Today I believe in love, because I'm in love. Tomorrow, I'll believe love doesn't exist, because it's over!"

She goes on to say that she's always found "real life" something of a bumpy ride, and that it probably has something to do with her childhood.

As a kid, she was sent to live with her mother's mother when her parents - avante-garde artists - were deemed too poor and feckless by the state to raise her. Said granny was a one-time maid, whose hair - thanks to her "hell of a life" - turned white at the age of 32. She had lots of stories to tell her tomboyish grand-daughter, one in particular about a military man - the love of her life - who one day disappeared... Delpy says that, for years, she was convinced her life was really just her granny's memories - that she was an old woman, trapped inside a young self. The feeling got stronger after her granny died. "I'm not New Age or weird," Delpy says quickly, "not religious at all. But it's a strong feeling and it's a very hard way to live, that you're not really real. Pretty scary, actually," she says with a shiver. "It's maybe a definition of schizophrenia!"

That Delpy is a teeny-weeny bit neurotic seems indisputable. Her worry is that people will think this is all she is. "The Bridget Jones thing. I hate that! It's such a stereotype! That if you don't have a husband and kids you can only be neurotic and insecure. I really tried to avoid that with Celine. There's the same prejudice if you're fat."

Delpy begins winding her hair up in a bun, her face suddenly as severe and stiff looking as that of an Aunt Sally doll. "I have this friend - she's kind of round, she's got huge tits. And people assume she's insecure about her body. But when I walk into her house she's half naked all the time! With her boobies like hanging around. Which I love!" A bigintake of breath: "People just aren't so predictable!"

She notes, for instance, that when she's directing, or writing, she's super-together; "eats well and sleeps well". It's only when she's acting that she becomes a fragile wreck. She thinks this is because the instinct of a "sensitive" artist is to hide away, but that as an actor, you have to constantly expose yourself. "It's a total contradiction."

So why not just give up acting? Her eyes widen in alarm. "But there's a side of me that just loves it - loves exposing myself. It's a type of masochism. It's sick. But I just can't stop it."

So if she was forced to choose between taking the lead in a Woody Allen film (one of her favourite directors) or directing Gael García Bernal (one of her favourite actors), what would she plump for? Delpy gives me a hardcore pout. "Why do I have to choose? It's not a fair question. I would lose my mind over it, but I'd figure out a way to do both, even if it meant working at night, all night."

The important thing is not to make others suffer for your art. In America, she explains, actors will simply walk out if they're treated badly. But it's a different story in France. As a young actress, she says, she was subjected to all kinds of abuse - because there were no "rules". Working on Bad Blood, for example, with the director Leos Carax, was "horrifying". "I was 15. and I hated him from then on. But he was very influenced by another person.... It's a long, twisted story. The point is, I don't like work and pain. I mean, I'm in pain, because that's what I like, but you shouldn't be allowed to torture others."

The PR pops her head around the door, to say that our time's up. "I'm talking about my poor childhood as an actress!" yelps Delpy. She also wants to know what happened to her pasta. "I'm starving!"

It turns out that the only reason she avoids butter is because she has a dairy allergy, which used to result in sporadic fainting. Now, thanks to olive oil, she's altogether more steady on her feet.

"You have to remember I'm not an American actress. I'm French. None of those diets, that horrible Atkins diet..." Delpy (a chatterbox obsessed with quiet; a daddy's girl desperate to leave home; a masochist who hates sadists and a cynic who adores being in love) has a big appetite. And praise be, she's hungrier than ever.