Early one grey Tuesday morning, a fleet of stylists, make-up artists and publicists is milling about in the hallway of a plush hotel suite overlooking London's busy Strand.

But upstairs in the bright, all-white lounge, all is calm, as Jourdan Dunn sits - her impossibly slender frame perched on a leather sofa - talking me through her forthcoming childrenswear collection for Marks & Spencer.

"I wanted to create something neutral, for both boys and girls," she says, in a voice that's softer than her stern-faced catwalk stomp implies. "There's a dress, but it's not too princessy or girly-girl," she adds, smiling. "[It's for] a girl who wants to rock her brother's oversized T-shirt as a dress, or the boy who wants to rock a cool sweat look."

This is the West London-native's first foray into retail beyond modelling, and she admits she was nervous at first that her androgynous sportswear-influenced designs wouldn't get the go-ahead by the iconic British brand.

"I didn't know if they'd be all for that, and when they said, 'We are very happy to take this on', I was like, 'OK, I think it's going to be a great collaboration'."

The Lil' LonDunn range is also influenced by her "very opinionated" six-year-old son Riley, who helped his mum by trying on samples.

Dunn notes there are elements of Riley" in the designs too, including 'R' motifs and a T-shirt featuring '09', "the year he was born".

"Once the final product was ready, Riley was like, 'Oh Mum, I like the hoodie; the hoodie's oversized and that's how I want it to be'," the 25-year-old says, beaming proudly. "The fact he notices those little details and he was happy made me like, 'Yay!'"

Famously discovered in Primark at the age of 15, Dunn has been modelling for nearly a decade, rising to the top of her game as the first black British model to make Forbes' top-earning models list in 2014, and amassing 1.6m Instagram followers along the way.

As well as countless campaigns, cover shoots and catwalk appearances, Dunn is one of that rare handful of models who have gained fame for being more than just a clothes horse - other accolades include hosting a cookery show on Jay Z's Life+Times YouTube channel, a role in Zoolander 2, and being named Style Influencer of the Year at this year's Elle Style Awards - and who are more than worthy of that elusive 'super' prefix.

Now Lil' LonDunn is under her belt too, is she plotting a full fashion line for grown-ups too?

"The option is definitely there. I just want to focus on the little people first and see what happens."

And then there's the acting...

"Opportunities keep on coming since I did Zoolander, so it's just now figuring out which one would be the right role," she says. "I would want to do something quite gritty, quite raw. Something very unexpected that people wouldn't put me in, [so they'd] be like, 'Oh wow, she can actually act'. I'm waiting for something like that to come up."

Fellow model-turned-actress Cara Delevingne is making waves in the movie world: has Dunn been asking her pal for advice?

"Not recently, but I'm super excited for her that she's doing something she's always wanted to do and has been so busy."

There's also talk of a cookbook, but Dunn says it's "very early stages".

Considering modelling has a notoriously short shelf-life, it's little wonder she's embracing every opportunity, and the future's looking bright.

"I feel this year is going to be the year of branching out and doing different things," agrees Dunn. "I'm really excited, and open to all of it."

JOURDAN ON...

...her childrenswear look: "My mum's not that girly and I had two younger brothers. That's the vibe with the collection; if it's a dress, it's going to be sporty."

:: Lil' LonDunn Pure Cotton Unisex Bomber Sweatshirt, ages 5-14, from £26; Lil' LonDunn Sleeveless Girls' Hooded Dress, ages 5-14, from £20 (www.marksandspencer.com)

:: Lil' LonDunn Long Sleeve Unisex Hooded Top, 5-14 years, from £15 (www.marksandspencer.com)

...her signature style: "I don't have a favourite designer, there's a wide range of brands I love, from high street like Topshop, and things like Adidas and Nike. I like to mix everything up, so I have high street and sportswear and designer. And then I love Balmain, Moschino... fun collections you can rock."

:: Love Moschino Jumper, £175 (Zalando.co.uk)

:: Pierre Balmain Slip-ons, £280 (Zalando.co.uk)

...real life vs online shopping: "Definitely online shopping, which is a saviour. I used to love to go and physically shop at the weekends, but it's kind of stressful. I want to go in and shop freely without feeling like I'm getting stared at or someone's going to come up and ask for a picture. So I avoid it now."

:: Topshop Airtex Stripe Panel Skirt, £35 (www.topshop.com)

:: Jaeger Jersey Knot Logo Sweatshirt, £60 (www.jaeger.co.uk)

...her last shopping spree: "I bought a bunch of sportswear online because I want to start hitting the gum again, so Stella McCartney and Adidas."

:: Adidas by Stella McCartney Sonic Mesh and Brushed Cotton Twill Sneakers, reduced to £91 from £130 (www.theoutnet.com)

...her off-duty look: "If I'm not going out, it's just loungewear, sweatpants - super-chilled. Today I'm wearing Pringle. Just a cool, easy jersey dress."

:: Pringle of Scotland Pleated Jersey Mini Dress, reduced from £650 to £227.50 (www.theoutnet.com)

:: Topshop Mix Pointelle Mesh Sweatshirt, £39; Bagged Jogger, £28; and Toulouse Lace-up Trainer, £52 (www.topshop.com)

GET THE LOOK

Forget the slew of glitzy gowns the Duchess of Cambridge has been wearing on her tour of India, we're most impressed with her chic-meets-sensible footwear: a pair of taupe wedges so practical she even managed a kick-about in them. Get your Mint Velvet Mink Grace Suede Wedges, £99, quick - before they sell out (www.mintvelvet.co.uk).

BUY IT NOW

A modern take on the classic quilted purse, this skinny little satchel comes with a slinky gunmetal chain, so you can wear it long across the body, or doubled up and half-length on one shoulder. Twice as nice.

:: JD Williams Satchel Bag with Slinky Chain, currently reduced to £7 from £32 (www.jdwilliams.co.uk)

FASHION FLASH

:: DELIVERY DONATIONS

A new survey suggests there are 350 million unworn items lurking in Britain's wardrobes, but who has time to do anything with them? Well, Oxfam has teamed up with CollectPlus, to make it easy to send off your cast-offs. Simply download a label from CollectPlus.co.uk, drop it off at one of 5,900 collection points and it'll be sent to Oxfam's online depot. You'll also be in with a chance of winning a £50 fashion voucher.

:: LINEN LEAPS AHEAD

Say 'sayonara' to silk and 'catch you later' to cotton: sales of linen have soared by more than 2000% compared to this time last year, according to George at Asda, who puts the spike down to the success of BBC spy drama The Night Manager. One linen product is being sold every minute, which we suspect is down to women wanting their other halves to look more like the show's star, Tom Hiddleston.

STYLE STEAL

Narciso Rodriguez bags usually retail around the £1,500 mark, but now you can get your hands on one for less than £300. The American designer has collaborated with sustainable luxury brand Bottletop on a pair of bags, as part of the brand's new Amazon collection. Made with Zero Deforestation leather and upcycled ring pulls, sales of the cobalt and black clutches help fund projects focused on vulnerable young people in South America, Africa and the UK.

:: Bottletop Luisa Leather Cobalt Clutch, £295 (Bottletop.org)