Earlier this week Jimmy Fallon put out a call on Twitter for people to share their biggest wedding fails for a chance to have their story featured on the Tonight Show. People shared memories of grooms forgetting their vows, falling during the first dance, and more. But when romance author Amy Pennza recalled that time her mother-in-law wore a white gown to Pennza's wedding, the Internet exploded. Here, Pennza shares the full story from her special day.

The summer I got married, there were a lot of weddings in our family. My sister-in-law got married in July, mine was in August, and my husband's close friend tied the knot in September. My mother-in-law was invited to all of them. So she had to buy three dresses for the weddings, plus outfits for all of the showers and parties that also come along with it. When it came time for my wedding, I didn't even think about asking her what she was going to wear.

On the day of my wedding, I was getting ready in a little chamber at the church with my bridal party. Then my mother-in-law walked in, wearing a wedding dress. I remember saying, "You could be the bride!" She cringed a little, and knew at that moment she'd made an error. I talked about it a bit with my bridesmaids, but then I didn't think about it for the rest of the day, because I was in a fog. Luckily, none of the guests brought it up to me (though I'm sure they talked about it among themselves). There wasn't a big, screeching moment of "What?!" So it didn't even register until a few days later.

Because to know my mother-in-law is to know that there is zero malice in her heart—the woman just can't resist a sale (and the dress was significantly marked down). My mother-in-law's frugality is the stuff of legends. When she goes to restaurants, she takes the ketchup packets and goes home and refills her bottles with them. She will pluck the olives and celery out of a Bloody Mary to use for a salad. The first time I learned of her antics was when I saw her Justin Timberlake doll—pristine in the original packaging—that she was keeping because she thought it would be worth money some day. She's got a closet with Furbies, Teletubbies, and more to sell.

It all dates back to her childhood. My mother-in-law grew up in a little area outside of Cleveland and was very, very poor. To the point of hunger. As a kid she would eat match heads. She didn't know it at the time, but that's the kind of thing you crave when you have a nutritional deficiency, and she was malnourished. The thing I admire about her so much is that despite her love of saving a buck, she's very generous. And an amazing grandmother (who has taught my kids not only to cook but to check candy vending machines for loose pieces).

But back to the wedding. Wearing the dress was not the only one of my mother-in-law's memorable moments on the big day. She had put a corkscrew in her purse before the ceremony so she could drink afterward. When it was over, she crouched on the sidewalk and opened the bottle of wine. When you're married in a church, you're supposed to leave your alter flowers behind to decorate the church. But she took them. The morning after, my hotel room was just filled with floral arrangements and food from the buffet. She kept all the leftovers. For weeks we ate the slices of cake she'd wrapped in napkins and put in a Tupperware. We ate all the wedding food she froze for a long time. She's probably ahead of her time in terms of being environmentally conscious, because she does not waste food.

To this day we still joke about the dress. On our anniversary we'll look at wedding photos and joke, "It's the two brides!" Or, "Bride one and bride two!" I'm still shocked, but she says she just didn't think about it when she bought the dress. She felt good and it was a steal, so she went with it. Now when we go to weddings I'll joke, "You're not going to wear white this time, are you?" But we know it's something she'll never, ever do again.

Samantha Leach is an assistant editor at Glamour. Follow her on Twitter and Instagram @_sleach.