Her co-star Nick Hewer was among the guests at the ceremony earlier this month.
The Countdown star met her millionaire husband while studying at Oxford. They broke up in 2009 shortly after she replaced Carol Vorderman on the gameshow, but reunited in 2011.
"It was only when we were walking down the stairs to the ceremony that I got a bit nervous," Riley told Hello.
"We were getting in position, ready to make our entrance when my dad stood on my dress. So he kind of fell over."
She added: "As soon as I saw Jamie, I was waiting for his reaction to my dress."
Hewer said of the bride: "Rachel is one of the most beautiful women in England. When you've got brains and beauty combined, then you've hit the jackpot - at least Mr Gilbert has."
Apprentice star Hewer praised his "extraordinary" co-star Riley earlier this year.