While most of the country was bedding down in readiness for another day of work on Tuesday night, the country's rich and famous were enjoying a glittering summer party to remember, courtesy of London's Serpentine Galleries. From supermodels to royalty, and pop stars to screen stars, London's Kensington Gardens was crammed to the treetops with A-listers.

Pharrell Williams
Pharrell Williams Brought A Surprise Set To The Serpentine Galleries' Summer Party.

US rapper Pharrell Williams was the surprise performer of the evening and treated guests at the annual fund-raiser to a neat half-hour set of his chart-topping, soulful pop. "We're in the best artistic environment we could be in," Williams said as the sun set and the moon rose over the leafy gardens.

Cara Delevingne
Party Girl Cara Delevingne Was Snapped In A Black Mulberry Gown.

Saying it had been "so much fun" to have performed at the Serpentine, Pharrell added afterwards "I love what the Serpentine Gallery does and that it's totally free so everyone can come and enjoy art," via the Evening Standard.

More: Pharrell Williams issues feminist speech at London concert.

"I think he's a very important artist in music. He's a serial inventor," Hans-Ulrich Obrist, the galleries' co-director said of his event's star performer.

Alexa Chung
Alexa Chung Looked Forward To AW14 In A Velvet Erdem Dress.

With Brioni being the event's first ever menswear sponsor, there were an array of dapper men sporting the label's designs, including Pharrell, Orlando Bloom and Keira Knightley's husband and Klaxons star James Righton, who hit the decks as DJ for the evening.

More: Cara Delevingne aiming for her own line of tweezers.

Perhaps three of the most photographed guests of the evening were actress Keira Knightley, model Cara Delevingne and Alexa Chung, who opted for Chanel, Mulberry and Erdem gowns respectively. Laid-back hair and understated make-up was the look of the night with most of the female guests keeping to the garden's fresh and natural theme.

Bradley Cooper Suki Waterhouse
Actor Bradley Cooper & Girlfriend Suki Waterhouse Were In High Spirits At The Summer Bash.

Other well-heeled guests spotted at the glitzy bash included Grayson Perry, Bradley Cooper, Suki Waterhouse, Emilia Fox, Lily Allen, Naomi Campbell, Mark Ruffalo, Tracey Emin, Mark Wallinger, Alexa Chung, Gemma Arterton, Alice Eve, Noel Gallagher, Sara MacDonald and Jack Whitehall.

As has been tradition for the past 14 years, the Serpentine Gallery invited a leading architect to design a temporary Pavilion outside the gallery in Kensington Gardens. Following the talents of Ai Weiwei (2012), Frank Gehry (2008), and the late Oscar Niemeyer (2003), Smiljan Radic has designed the 2014 Serpentine Gallery Pavilion - a doughnut-shaped fibreglass shell resting on stacks of large rocks, which was unveiled at this week's Summer Party.