Best Dressed Celebrities at the Serpentine Gallery Summer Party: Alexa Chung, Gemma Arterton, Samantha Barks & Keira Knightley

It was one of those perfect London summer evenings when fashion takes center stage.

At the Serpentine Gallery Summer Party in Hyde Park, Alexa Chung, Gemma Arterton, Samantha Barks, and Keira Knightley brought effortless glamour to the season’s most talked-about social gathering.

Trading red-carpet drama for chic, pared-back elegance, each star delivered a look that captured the easy sophistication of warm-weather style—proof that sometimes understated really is unforgettable.

Alexa Chung, Gemma Arterton, Samantha Barks, and Keira Knightley turned the Serpentine Gallery Summer Party into a style showcase, each pairing standout designer dresses with chic footwear that highlighted their individual flair in London, England, on July 1, 2014 (Credit: WENN / Daniel Deme / Lexi Jones)

Here are some of our favorite standout dresses from the event:

1. Minimalist Chic: Alexa Chung in Erdem & Pointed Flats

Not related to Jamie Chung, trendsetter Alexa Chung brought her signature effortless style to the Serpentine Gallery Summer Party in London, arriving in a strapless Erdem Fall 2014 dress. At first glance, the piece appeared to be a simple black gown, but closer inspection revealed luxe touches—the lace hem, velvet finish, and intricate stitching that gave the dress quiet depth.

Still, the look felt unexpectedly autumnal for a high-summer soirée, with its heavy woven detailing and moody undertones. A splash of lively accessories—think playful color or bold jewelry—might have brightened the ensemble, echoing the more season-appropriate choices of fellow guests. Instead, Alexa stayed true to her minimalist instincts, finishing with flat ankle-strap shoes and a classic red lip.

Alexa Chung kept it chic in a strapless black Erdem dress paired with pointed ankle-strap flats for a minimalist yet refined finish

At 5 ft 7 ½ in (171.5 cm) and wearing a US shoe size 8.5, the British presenter is taller than the national average, which allows her to pull off flats without losing presence on the red carpet. The choice grounded the outfit in understated cool, even if some might have wished to see the dress on Rooney Mara or styled with a little more summer flair.

2. Lady in Red: Gemma Arterton’s Prabal Gurung Two-Piece & Ribbon Sandals

Most monochrome looks can fall flat, but Gemma Arterton proved that head-to-toe red can be both striking and sophisticated. Attending the Serpentine Gallery Summer Party in London, the British actress lit up the evening in a Prabal Gurung Resort 2015 two-piece ensemble crafted from textured jacquard.

The cropped top paired with an asymmetrical flounced tulip skirt highlighted her toned midriff and legs with playful ease.

Gemma Arterton lit up the carpet in a vibrant red Prabal Gurung two-piece set, styled with playful matching red ankle-tie sandals

Leaning into the vibrancy of the look, Gemma styled it with red patent sandals adorned with ribbon ankle ties—a detail that added youthful flair to the bold silhouette. Blown-out tresses, chandelier earrings, and barely-there makeup completed the ensemble, keeping the focus on the fiery monochrome statement.

Standing 5 ft 7 in (170.2 cm) and wearing a US shoe size 8, Gemma possesses the stature and proportions to pull off dramatic colors and shapes effortlessly. This was easily one of the standout looks of the evening—a perfect balance of sultry and spirited.

3. Metallic Elegance: Samantha Barks in Lanvin & Tonal Pumps

Samantha Barks embraced the monochrome trend in a metallic-pink Lanvin Spring 2014 bustier dress, but her styling didn’t quite capture the same magic as Gemma’s bold red look.

The British actress’s frock, finished with raw edges, frayed trims, and pintuck detailing that cinched the waist, shimmered beautifully under the lights and flattered her figure with ease.

Samantha Barks shimmered in a metallic pink Lanvin dress, complemented by coordinating blush pumps and a ribboned clutch

While the dress itself was a showstopper, her choice of tonal pumps, ribboned clutch, and Wilfredo Rosado honeycomb pavé earrings kept the look a little too safe.

A touch of contrast—perhaps rose-gold accessories or a sleek metallic sandal—would have elevated the ensemble from pretty to unforgettable.

Standing 5ft 5 ½ (166.4 cm) tall with a US shoe size 8, Barks has the frame to carry bolder shoe choices that could have turned this into one of the night’s standout fashion moments.

4. Ethereal Glamour: Keira Knightley’s Chanel Beaded Ensemble & Peep-Toe Heels

Keira Knightley, accompanied by husband James Righton, delivered an ethereal moment in Chanel at the Serpentine Gallery Summer Party.

True to her longstanding relationship with the French fashion house, the British actress selected a look from the Resort 2015 collection—a multi-colored, asymmetrical creation with a beaded bodice and a skirt layered with delicate floral appliqués.

Keira Knightley stood out in a beaded Chanel gown with floral appliqués, subtly grounded by white peep-toe heels alongside husband James Righton

At first glance, the flowing white fabric suggested a layered skirt, but on closer inspection, it revealed itself to be wide-leg linen trousers, adding a surprising twist to the design. While some might imagine Diane Kruger or Marion Cotillard wearing the same piece with a sleeker, stripped-down silhouette, the layered whimsy felt perfectly in tune with Keira’s romantic, bohemian style.

At 5ft 6¼ (168.3 cm) tall and wearing a US shoe size 9, Keira often gravitates toward understated footwear to complement her couture gowns. Though her shoes remained discreet here, the overall look was quintessentially her—polished, poetic, and unmistakably Chanel.

Keira Knightley’s Chanel dress with a beaded bodice and a skirt with floral appliqués