The 'Anna Karenina' star chose to marry her boyfriend James Righton in the pale pink designer frock, which she first wore at the pre-BAFTA party in 2009, because she wanted to get hitched in a gown with sentimental value, reported Contactmusic.
"It was something old, something new, something borrow and something blue. I had something old, which was the dress. But it's a dress that I've always had a brilliant time in.
"Every time I've worn it they've been brilliant nights. I wanted to be able to dance the night away and you can definitely dance in that dress," she said.
"The shoes and jacket were very beautifully designed by Karl Lagerfeld and made especially for me, so they were very new! I had my friend's ring for something blue and another friend's necklace for something borrowed.