Cara Delevingne found it a ''challenge'' to create a bag that suited her lifestyle.

The 22-year-old model has collaborated with Mulberry on an accessories collection and says it was important for her to design something ''functional'', as well as ''cool and beautiful''.

She said: ''They're really practical. It was important for me to design something functional that fits with my lifestyle and the backpacks are it.

''The bags are just what I wanted them to be - cool and beautiful. I had lots of ideas but the biggest challenge was to create something that could keep up with my lifestyle because I'm always on the move.''

Cara - who made into Forbes magazine's highest-earning models list this year with a huge $3.5 million - enjoyed every minute of the design process.

She said: ''The whole process was amazing and I'm very happy with the final designs.''

And actress Gemma Chan is already a fan of Cara's collection.

She gushed: ''I love Cara. She's a great girl and I think the bag collection is just brilliant. You can wear them several ways and they go with everything.''