Candice Huffine - who was the first plus-size model to appear in the Pirelli calendar and on the cover of Italian Vogue - will front the campaign for the new collection.
"The fact that River Island is extending their sizing while staying true to their brand is perfection," Huffine said. "It's clear that they have thought about a curvy woman's body and designed accordingly, while giving her exactly what can be found on the high street at any other size. A plus-size collection doesn't need to be made totally different, it just needs to be made to fit."
The collection arrives in store and online at Riverisland.com in March, with prices ranging from £6 to £80.