Tara Fitzgerald and Justine Waddell, the stars of the BBC's Christmas drama The Woman in White, are having a fit of giggles. The two actresses are experiencing tremendous difficulties walking in high-heeled strappy sandals for the Tatler photo shoot. 'They're too high,' they squeal, tripping up once again.

Tim Fywell, director of The Woman in White, confirms that giggling was a constant feature on the set. 'They did laugh a great deal, but it was probably the hysteria of long hours in tight corsets and hair extensions.'

Tara and Justine became very close while shooting the spooky gothic drama, which also stars Simon Callow, James Wilby and Andrew Lincoln. Adapted from the classic novel by Wilkie Collins, The Woman in White tells of two sisters who find themselves drawn into a maelstrom of secrets, crime and passion. "It has fascinating themes,' says Tara, who plays the elder of the sisters, the strong-minded Marion. 'Male domination, the power of money, the idea that women are used for bartering...' Justine portrays the innocent and beautiful Laura, who is to be married to a man she doesn't love and whisked off to a remote country house, where the thrills and chills really begin.

Tara, 29, is still basking in the success of her last film, the black comedy Brassed Off, in which she romped with Trainspotting's Ewan McGregor. Petite, with defiant cheekbones and a huge smile, Tara exudes mischievous sex appeal. She adored working with McGregor. 'Ewan, he's great,' she says, drawing on the first of many Marlboro Lights. 'He's got that twinkle in his eyes. He's definitely got "it".' Many of Tara's previous co-stars have also had 'it'. 'Ewan, Ralph [Fiennes], Hugh [Grant], Rupert [Graves]...' she says, 'they were all great. I can see why they're the stars they are.'

Her own journey to stardom began two weeks after she had graduated from drama school. She landed a major role in Peter Chelsom's debut film Hear My Song, and went on to dazzle critics and audiences alike when she appeared opposite Peter O'Toole in the West End production of Keith Waterhouse's Our Song.

She acquired a racy reputation after declaring she wasn't bothered about taking her clothes off in the TV series The Camomile Lawn, and reinforced it when playing the seductress in Anglo-Saxon Attitudes. 'There was a time when I was accused of being evangelical about nudity, which is the last thing I am,' she says, laughing.

Other hits followed, including the films Sirens and The Englishman Who Went Up a Hill and Came Down a Mountain, both of which saw her pairing up with Hugh Grant. And then there was her award winning performance as Ophelia opposite Ralph Fiennes in Hamlet on Broadway. 'Everyone came to see it,' she remembers. 'Demi Moore, Steven Spielberg, and anyone and everyone you can think of. It was magical.'

Tara's Anglo-Irish family has strong theatrical roots -- her great-aunt, Geraldine Fitzgerald, appeared with Laurence Olivier in the 1939 film of Wuthering Heights. Tara herself knew she wanted to be an actress 'from the age of four'. Her childhood was not easy. Her artist father left her mother when Tara was three and comitted suicide eight years later. She left school at 16 to waitress her way around Europe, returning to London three years later, and eventually securing a place at the Drama Centre.

Tara now ranks alongside Kate Winslet as one of Britain's bright young talents, altough Hollywood has yet to be conquered. She will remain in Britain for her next film, Soho, a tale of London gangsters in the Fifties and Sixties, already billed as Britain's answer to The Godfather. Her current priority, however, is finding somewhere to live. This summer she split up with her boyfriend of five years, Soldier Soldier star Dorian Healy, and moved out of their flat in Barnes. 'I'm all right,' she mumbles. 'It's never nice.'

Tara has been linked to one of the cast of The Woman in White, Andrew Lincoln, better known as Egg from This Life, but denies it rigorously. 'It's just gossip. There really is no one else for the time being.'

Justine wanders over to steal a cigarette from Tara. Unlike her co-star, she is shy and obviously nervous about the interview and photoshoot, inquiring constantly:' I hope that doesn't seem pretentious', or 'I don't want to appear precocious or too serious.' Dressed in baby-pink cotton cardigan, loose black trousers and loafers, she has the ethereal beauty of the classic English rose, in contrast to the more earthy Tara, who can now be heard arguing forcibly about the merits of Loaded on the far side of the room.

The Woman in White sees South-African born Justine, 21, in her biggest role to date. She is, for the moment, juggling her acting and university careers. Social and Political Science at Cambridge has been temporarily put on hold.

Social and Politcal Science, however, has become used to taking a back seat. Ever since Justine made her university acting debut s Juliet, directors have been queuing up to offer her professional roles. First, Countess Nordstrom in Bernard Rose's film of Anna Karenina, released last July. Then came the role of Sacha in Jonathon Kent's Almeida Theatre production of Ivanov in February, which starred Ralph Fiennes and brought Justine to the attention of Fywell.

The director had been looking for some time for a girl who could play Laura. 'You get a lot of sassy young actresses,' explains Fywell, 'but very few who can convey that innocence and freshness.'

'When you talk about childhood dreams this part is as good as it gets,' says Justine, her shyness finally giving way to enthusiasm. 'Unbelievably beautiful costumes, a wonderful male lead [Lincoln] and the whole gothic thing. It was wonderful.' Her next challenge is the title role in Tess of the D'Urbervilles for ITV, which will surely make her a star. And confirm her as a great screen beauty? 'No! No! No!' Justine protests. 'Anyway, Tess seems to spend most of her time milking cows.'