Sienna Miller flashes her underwear in VERY risqué Halloween outfit while Alex Scott and girlfriend Jess Glynne bring the fun as they dress up as McDonalds mascots at Casamigos’ Haunted House Of Friends bash

Sienna Miller flashed her underwear in a mesh risqué Halloween outfit as she attended Casamigos’ Haunted House Of Friends bash on Thursday night.

A host of star-studded guests partied inside the festive Tequila soirée at Jack Solomons in London.

Model and actress Sienna, 42, wore the very sexy ensemble with a black crown while boyfriend Oli Green, 27, was covered in fake spiders.

Alex Scott, 40, and girlfriend Jess Glynne, 35, brought the fun as they dressed up as haunted McDonalds mascots.

The couple, who have been dating since last year, got stuck into this year’s Halloween party with their jaw-dropping costumes.

Alex Scott, 40, and girlfriend Jess Glynne, 35, brought the fun as they dressed up as haunted McDonalds mascots

Alex was dressed up as Hamburglar while Jess wore the iconic Ronald McDonald ensemble.

The loved-up pair wore matching stripe tights and carried a McDonalds Happy Meal into the bash to eat and go with their outfit. 

Paloma Faith dressed to impress as a scary cheerleader as she attended Maya Jama’s annual star-studded Halloween party in London before heading onto Casamigos’ bash.

The singer, 43, looked amazing in the ‘devil’s’ black and red mini dress which she teamed with an oversized red varsity bomber jacket.

Paloma added inches to her frame in a pair of black lace up knee high boots which she wore over knee high socks and fishnet tights.

She completed her spooky party look with some gory makeup including a cut on her cheek, black smudged eye shadow and red smeared lipstick. 

Lottie Moss looked incredible as she wore a bright pink dress with long gloves, inspired from Marilyn Monroe’s 1953 outfit. 

Isobel Richmond and Lennon Gallagher also attended the event in their scarily spooky looks. 

Model and actress Sienna wore the very sexy ensemble with a black crown while boyfriend Oli Green, 27, was covered in fake spiders

Paloma Faith dressed to impress as a scary cheerleader as she attended Maya Jama ‘s annual star-studded Halloween party in London before heading onto Casamigos’ bash

Lottie Moss looked incredible as she wore a bright pink dress with long gloves, inspired from Marilyn Monroe’s 1953 outfit

Isobel Richmond and Lennon Gallagher attended the event in their scarily spooky looks

Jaime Winstone got the party started in her glamorous Egyptian outfit and wore scary white fangs

Jamie pictured with Fran Cutler

Singer Olly Alexander looked adorable in his Halloween outfit, sporting fluffy ears and a matching jacket

Sugarbabes star Mutya Buena put on a very leggy display in a thigh-high split gown

Meanwhile, Diana Vickers wore the iconic Regina George look from Mean Girls

Jaime Winstone got the party started in her glamorous Egyptian outfit and wore scary white fangs. 

Singer Olly Alexander looked adorable in his Halloween outfit, sporting fluffy ears and a matching jacket. 

Sugarbabes star Mutya Buena put on a very leggy display in a thigh-high split gown. 

Meanwhile, Diana Vickers wore the iconic Regina George look from Mean Girls.