The wife of England footballer Wayne Rooney models the contrast sleeve jackets, prints and tailored pieces in the '50s-style shoot.
"I feel like I've come into my own this season and think this is my best collection yet!" Coleen said.
"As always, I have designed my collection to suit women of all shapes and sizes and I'm really excited to get it out there!"
Brand director at Littlewoods.com Gary Kibble added: "Coleen continues to be a fantastic designer and Style Ambassador for Littlewoods.
"Her attitude and sophisticated sense of style ensures every collection is a success.
"Whilst husbands and boyfriends are glued to the Euros, Coleen's new collection will provide a welcome distraction for female shoppers."
Coleen became a style ambassador for Littlewoods.com in June 2010 and designed her first collection for the company for its Spring/Summer 2011 range.
Including her swimwear designs, the current AW12 range is Coleen's fifth for the company.
Clothes in the new range are available in sizes 8-24 and are priced from £20 to £125.