The 28-year-old actress made no secret of her decision, calling the gown her "something old".
Just last week, Keira revealed that her wedding dress was now covered in red wine stains, after she had worn it out to a party and her friend knocked into her.
"It's quite impressively splattered," she said. "But, hey, a good night is a good night and when a dress has had its time, maybe it's had its time."
CLICK ON PHOTOS FOR GALLERY OF WEDDING DRESSES
For brides that want to follow in Keira's footsteps, and invest in a dress they can wear over and over again, wedding boutique Churchgate Porter, based in East Sussex, has put forward various options.
Click on the photos for a gallery of wedding dresses.
Owner Louise Hill has shared her top five tips on what brides-to-be should consider when choosing their 'non-wedding dress' wedding dress...
Having the right style is imperative to wearing your dress again. Don't go for a big tiered ruffled skirt and tight bodice — stick to more elegant simple styles made from silk or satin. Avoid too much lace and go for simple straps or long sleeves.
Low back wedding dresses are very popular at the moment which is a great look for a dress to be worn to a cocktail party or black tie event. Delphine Manivet's signature wedding dress look is a two piece outfit, consisting of a simple top tucked into a long lace or tulle skirt. This style is perfect for wearing after your wedding day.
If your dress is simple and elegant then any colour will work. At the moment we are seeing many colours on the bridal catwalk from blues to blush to black and white. All of these colours are perfect for a dress to be worn after your big day. We do associate white with weddings however a simple white dress can look stunning on your summer holidays or a lazy afternoon on the beach.
If you choose a shorter length dress then it is easy to turn it into a cocktail dress or summer party dress. You could always add embellishments such as a brooch or vintage belt. The one thing you can't get away with after your wedding is a long train, so make sure you can have this taken off without ruining the style of your dress.
Look at ways your dress can be changed. Could you have it shortened, the sleeves removed, or even dyed a different colour? Just by adding a jacket and changing your shoes will completely change the look of your dress. If you add a biker jacket you have a complete rock chick look.
5. Be proud
Keira Knightley wore her wedding dress again and was proud of it. Don't hide the fact you are wearing your dream dress, you should be proud that you have an amazing dress you can wear again and again.