The Sarah Burton design is available for purchase on Net-a-Porter.com for £1,995.
It is virtually identical to the one worn by Kate Middleton's sister for April's royal wedding, minus the lace sleeve detail and with a zipper instead of buttons down the back of the dress.
Net-a-Porter described its star product as "an exquisite choice for your wedding day."
Pippa's bridesmaid dress was an immediate sensation on the day of the royal wedding, triggering a stream of appreciative comments on Twitter as soon as she stepped out of the car.
The cowl-neck, silk creation reportedly cost £20,000 to make and has prompted a string of replicas - but none designed by Sarah Burton, until now.
Pippa recently landed a book deal for a guide to children's party planning and was spotted out at a London ice rink launch last night (above, first photo) after splitting from her boyfriend earlier this month.