Keira Knightley and Sienna Miller are about to do for floral, tea dresses and cardigans what Sarah Jessica Parker did for gladiator heels when she stepped on to the big screen in a knock-out pair of Dior Extreme platforms earlier this year - and that's catapult them to the top of the season's fashion wish-list.

Unlike Sex and the City however, which is just one big fashion parade dressed up as a movie, Knightley and Miller's latest film, The Edge of Love, is far from a fashion flick. It's just that the pair look so darn gorgeous in their wartime ensembles, complete with knee-high socks and wellingtons, you want to steal their look.

Set in London and rural Wales during the 1940s, The Edge of Love is a romance written by Knightley's mother, Sharman Macdonald, and based loosely on the life of Welsh poet Dylan Thomas (Matthew Rhys), his wife Caitlin (Miller) and his childhood sweetheart, Vera Phillips (Knightley). However, the plot is sometimes overshadowed by the clothes, which one British newspaper described as a "wartime make-do-and-mend look".

The wardrobe, styled by costume-design veteran April Ferry, features floral tea dresses and cardigans - the kind of well-worn, chunky cardies you'd find at the local op shop - high-waisted pencil and looser, pleated skirts, pussy-bow blouses, woollen pea coats, thick, knee-high socks and folded-down wellies. On occasion, the look moves from countryside chic to 1940s glamour - think strong red lips, long gloves, seamed stockings and hair set in waves - a 'do that is fast becoming the must-have red-carpet coiffure.

When the film opened in Britain in June, it sparked copycat looks along that country's high streets. Fast-fashion chain Oasis created an entire Edge of Love collection, while H&M and Topshop were racked to overflowing with '40s-style tea dresses and chunky knits.

Given what Knightley did for emerald-green evening dresses in her role as the glamorous Cecilia Tallis in Atonement, and what Miller does for any item of clothing she slips on - from gypsy skirts to striped jumpers - it is hardly surprising that wartime chic is enjoying a revival here, too.

Everyone from Dotti to Forever New is channelling the picnic-in-a-blizzard looks from the movie with floaty dresses, pretty florals, delicate blouses, chunky cardigans and long, woolly socks.

Cohen et Sabine, Marnie Skillings and Leona Edmiston - pretty florals; Melanie Cutfield and Rose & Ruby - floaty tea dresses; Brigid McLaughlin, Trelise Cooper and Alannah Hill - feminine skirt-and-cardigan ensembles, also give a nod to '40s fashion.

Given Miller's track record, we could be in store for some interesting trends over the next 12 months or so. Among other roles, the 26-year-old style icon is set to play a sexy, gun-wielding femme fatale in G.I. Joe: Rise of Cobra, and Maid Marian in Ridley Scott's much delayed take on the Robin Hood story in Nottingham (with Russell Crowe).

Get out your petticoats, girls.