The former Spice Girl said that she "always dreamed of designing a collection", and spoke about her love of fashion from a young age.
The 39-year-old designer said in a feature for Skype: "I've always loved fashion and I was that kid that used to watch my mum get ready and think, 'wow you look amazing'.
"The first schoolbag that I had was actually a Gucci carrier bag - not a proper Gucci bag, a carrier bag - that I would lug all of my schoolbooks to school in and I used that day in and day out until the bottom of the thing fell out."
She also opened up about the difficulty she faced breaking into the fashion industry after her success in music, explaining: "I was a Spice Girl married to a footballer, I was trying to do something that no one had really done before.
"The first dress that I wore in the Spice Girls that everybody thought was a little black Gucci dress was actually from Miss Selfridge, it wasn't really a little, black Gucci dress, I couldn't have afforded a little, black Gucci dress and Virgin Records certainly weren't gonna buy me a little Gucci dress."
The mum of four added that she "felt embarrassed" to mention that she was working on a dress collection to Marc Jacobs.
She said: "I mean this was Marc Jacobs, somebody that I have an enormous amount of respect for, and have done for many, many years, and to him, I was a Spice Girl, and I was married to David Beckham. I didn't wanna tell Marc Jacobs I was working on a collection of ten dresses."