Director Matthew Vaughn has a track record for turning under-the-radar actors into overnight stars. He was the one who put a pre-Bond Daniel Craig on the map in Layer Cake and launched Chloe Moretz as the tiny, foul-mouthed Hit Girl in Kick Ass. So when Vaughn picked an unknown actress called Sophie Cookson to play the lead role in his new film Kingsman: The Secret Service - despite Harry Potter star Emma Watson being widely tipped for the part - there was understandable buzz.

As I watch Sophie Cookson slip onto a banquette opposite me at Soho restaurant Dean Street Townhouse, it’s hard to ignore a few striking similarities to the world-famous actress she beat to the part. Like Watson she is fine-featured, petite, with drama school vowels, and in today’s chic high-necked dark floral dress and oversized scarf there’s an undeniable young Brit thesp vibe to her. Did she know she had such high profile competition when she auditioned? “Not a clue” she says, shooting me a thank-god-for-that look “that would have really piled on the pressure wouldn't it?”

Kingsman is a gloriously silly James Bond spoof created by Vaughn with the screenwriter Jane Goldman; every bit as brilliant as the pair’s 2010 cult hit Kick Ass. 24-year-old Cookson – who plays new agency recruit Roxy - has a handful of previous credits to her name, including a part in Sky miniseries Moonfleet with Ray Winstone, but Kingsman is the film that will put her on the map when it hits cinemas this week. So who exactly is this girl who sprung from nowhere to score one of the hottest movie roles of the year? We settled in with a mint tea and quizzed her to find out.

How does it feel to be in a movie with all these massive stars?
“Just so surreal. The big one for me was Michael Caine. I remember shooting a scene with him in this tiny library and thinking, ‘my grandmother would have loved this.’”

On the rise: The Kingsman actress Sophie Cookson

Who are you taking as your plus one to the premiere?
“Oh don’t, it’s a political nightmare! My Dad keeps emailing going ‘well I can do this date, and this date and this date’, I’m like ‘um, I didn’t invite you yet!’”

Are there any other actors in your family?
“Well my grandmother would have said it all comes from her because she once played Jane Eyre in a school play. But otherwise my mum’s an English teacher and my Dad is in finance, so no! I have a little brother who is very musical so there is a creative streak.”

The Kingsman actress Sophie Cookson

Were you that girl who always got the best parts in school plays?
“Ha - yes I was hungry for it! Though to be honest I wanted to do everything when I was younger. I wanted to be a vet, an illustrator, even a translator. But I decided after school that I was really going to regret not giving acting a go so I went to the Oxford School of Drama.”

You were still there when you got cast in a Sky miniseries...
“Yes I was halfway through my final term when I left to film Moonfleet with Ray Winstone. Being on a set for the first time is like starting in a new office and not knowing where anything is, except every day it changes!”  

The Kingsman actress Sophie Cookson

Have you done any red carpet yet?
“Yes, but it’s still a whole new world to me. Miu Miu have been very kind lending me stuff and I went into Chanel to pick some things out. I was so nervous about what to choose I went for a skirt and jumper - safe territory! I have to say it’s just nice to wear colour as at drama school our uniform was all black and no-make-up for three years. As someone who spends a ridiculous amount of time deciding what to wear that was probably a good thing.”

Did you like the denim we styled you in for the shoot?
“I had never seen so much denim in my life, it was quite overwhelming! It reminded me how much I love that really grungy, 90s look. I actually showed up in a pair of dungarees so I was already in the zone. I also loved the denim MiH jumpsuit, it reminded me of the pinstriped ones we wore filming Kingsman.”  

If you were a piece of denim what would you be?
“I’d probably like to be a denim jacket, because they’re likable, dependable and they go with everything!”

The Kingsman actress Sophie Cookson

Kingsman: The Secret Service is released in cinemas January 29th