It's my party and I'll dress how I want to? Rita Ora celebrates 22nd birthday with pal Cara Delevingne in bizarre outfit

PUBLISHED: 08:38, 27 November 2012 | UPDATED: 08:49, 27 November 2012

Rita Ora turned 22 on Monday and appropriately, she partied like it was her birthday.

Joined by model pal Cara Delevingne and Tinie Tempah, the RIP singer attended a gig by Big Sean at the O2 in Shepherd's Bush in London and later joined him backstage for an after party.

But despite going to a rap gig, the star was dressed rather bizarrely in a white shapeless dress and large fur coat and experimented with a new sleek hairstyle.

Happy birthday! Rita Ora celebrated her 22nd birthday attending a Big Sean gig with pal Cara Delevingne

Even though her loose-fitting white dress looked more like a nightgown than a birthday outfit, the star didn't seem to care and left the venue with a big smile on her face.

As it was a chilly evening, the star was appropriately wrapped up in a huge fur coat and a black beanie that kept her warm.

And true to her pop star lifestyle, Rita changed her usual curly bob hairstyle into a sleek and long blonde do, with a fringe to change things up on her birthday.

Pals: The two ladies joined the rapper and Tinie Tempah backstage after the gig at the O2 in Shepherd's Bush

Birthday outfit: The star wrapped up in a large fur coat, but wore a shapeless white dress underneath

Rita was joined by Burberry model Cara Delevingne on her big night out, and the two ladies were spotted going over the evening as they left the O2 following the gig.

The latest Victoria's Secret model was a little more casually dressed for the evening, sporting bright red jeans and a jersey top and looking fresh faced and make-up free.

The two friends were in the countryside earlier in the day and went home after the gig to celebrate with friends and a Chinese takeaway, according to their Twitter accounts.

Tweeting day of fun: Both girls took to their social media accounts to chronicle Rita's birthday

Taking over Hollywood: It's no wonder Rita sports such a big smile as she recently landed her first movie role

And the birthday girl had a lot more to celebrate than turning 22, as it was announced she bagged her first movierole in the upcoming flick The Fast and the Furious 6.

She reportedly took over the role from Rihanna, who was cast earlier but had to back out due to her busy schedule.

A source told The Sun: 'Rihanna impressed movie bosses with her role in Battleship. But schedules didn’t work out and Rita really shone during castings.'