25 Lessons in Effortlessly Cool Style from Fashion Icon Jane Birkin

The 18-year-old actress, who was starring in Graham Greene's Carving a Statue at the time, coquettishly peeks out from behind a column in a stylish French-inspired uniform: a crewneck sweater, cropped pants, and ballet flats.

A fresh-faced Birkin, pictured here at 20 years old, heads out for shopping in London sporting flared pants, a statement belt, and a layered jacket.

A young Birkin has just landed the leading role in the film Wonderwall. Here, she pauses in a black vest and pants, aptly juxtaposed against a ruffled blouse.

Birkin, whose first marriage was to composer John Barry at the age of 17, shows here that an uncomplicated ensemble and scene can still make a stunning statement (and photograph).

Birkin and George Harrison, who wrote the soundtrack for the film Wonderwall in which she starred, stop for a photo while at the Cannes Film Festival. She steals the scene, thanks to a floral mini dress and woven basket doubling as a handbag.

Here, Birkin is captured on the grounds of the Parc de Saint-Cloud showing off a python vest over a maxi dress by Jean Muir and a bold yellow gold necklace by Zolotas.

Photographed at their Chelsea flat in London, Birkin poses with Gainsbourg and modernizes a feminine ruffled blouse with a sleek black skirt and wide leather belt.

Birkin elevates her travel look while boarding a plane bound for London with an all-black ensemble that puts the airport athleisure of today to shame: a wool coat, sweater, shorts, and high socks look stylish and comfortable.

While being photographed for Vogue, the model embodies the mantra more is more. A suede tunic and pants designed by Ossie Clark and adorned with the decade's fabulous fringe allow Birkin a playful moment.

The Parisian-born Gainsbourg, who was a lyricist, poet, and singer-songwriter, and Birkin, wearing a lace top and white denim, lounge on the beach at the Cannes Film Festival.

Sometimes, it's less about the clothes and more about the styling: Birkin and mentor-turned-lover Gainsbourg stroll through the courtyard of the French National College of Fine Arts in Paris, both outfitted in black coats with upturned collars.

Birkin, in an chic black dress with a plunging neckline, tries on jewelry by Boucheron with Gainsbourg (a jewel collector himself) at The Most Beautiful Jewelry in the World exhibition.

On display here, Birkin's iconic beauty look that is still being copied by femmes today: the perfectly mussed fringe bang, the dash of mascara, and the natural face.

Birkin personifies playful yet pulled together, thanks to a flared denim pant, rolled white tee, and her trademark just-right tousled hair.

Here, her version of the little black dress: Birkin strikes a pose in a summer-friendly mini dress and layered coin necklace, proving that sometimes the only accessory you need is one great statement piece.

Birkin and Gainsbourg make a stylish entrance at Heathrow airport, with Birkin sporting her classic tights, shorts, and coat combination—all carefully downplayed by her signature woven tote.

Birkin and Gainsbourg take it all in on a trip to Tokyo in 1971, and she looks the part of modish traveler in a peasant-style dress and tall suede boots with her iconic basket handbag in tow.

Birkin, who could boast King Charles II as an ancestor, jaunts down a London street in velvet shorts by Vicky Tiel, tights, and an elegant overcoat.

Caught on holiday in the Cote d'Azur in July of 1973, Birkin embodies summer spirit in an eyelet ruffled blouse and platform heels.

While on the set of the French film Je Suis Serieux Comme Le Plaisir, Birkin wears a black blazer and pants with a button-down blouse, proving that classic pieces are always chic.