Kylie Jenner shows off her sexy style in skinny jeans and a simple vest as she steps out ahead of her milestone 18th birthday

She has a week to go until she rings in her milestone 18th birthday.

But Kylie Jenner didn't appear to be too excited about her upcoming celebrations as she stepped out near her home in Calabasas, California on Monday.

The teen star did, however, manage to look as stylish as ever with a typically effortless casual ensemble as she emerged with her close pal, singer Pia Mia.

Looking slightly moody as she walked across a car park, the star showed off her trademark style, sporting a pair of skintight grey and cropped skinny jeans with Nike trainers in a similar shade.

She kept it clean-cut and fuss-free with a white vest top tucked into the high-waisted denim, while covering her face with a pair of oversized shades.

Show stealer: Kylie, 17, was joined by her close pal Pia Mia, who rocked a slightly more eye-catching look as they went to get some drinks after having dinner together. 

Outfit change: Kylie later shared a snap of herself with singer Pia Mia, having changed into a torso-revealing crop top. 

According to TMZ, Kylie will celebrate her milestone birthday at the Beachclub Montreal, a mini party island decked out with a pool, A-list DJs, its own beach and alcohol on offer.

It's claimed the teen will be paid between $100k and $200k just for showing up to the event and partying with her friends.

It's believed the club's owner, Olivier Primeau, will have Kylie flown into the bash by helicopter, where she'll land on a luxury boat that will dock next to a table flooded in bottles of champagne.

She'll also blow out the candles on a $3,000 birthday cake and, according to the site, tickets for the event are retailing between $40 to $150.

Denial! Kylie was forced to take to Twitter to deny rumours that she was engaged to her rumoured boyfriend, rapper Tyga