After her turn wearing the spring/summer range, the Made in Chelsea star returns to the brand to launch its new autumn/winter 2012 designs.
"I love fashion and enjoy modelling, and was overwhelmed with the response to my last campaign for Lipsy, "Mackintosh said.
"The VIP range makes the job feel easy - as soon as you put on any of the dresses, you feel instantly glamorous!
"So much work goes into these designs to give them a sense of the bespoke and so you can't help but feel great - you couldn't have a bad night out in a Lipsy VIP dress!"
The collection launches in-store and online today (August 7) and prices range from £90 to £140.
The autumn/winter range adds 18 new styles featuring beadwork, tulle appliqué and jewel embellishment.
Mackintosh's favourite new design is a contrast vintage cream prom-style mini dress with sequined bustier and full kick skirt.
Other clothes in the range are a full length all-over midnight black sequin gown with thigh length leg split, floor-length halter dress with ruched bust and bejewelled satin detail, knee length asymmetric mink cocktail dress with chiffon overlay and appliqué flowers.