(Kayt Jones/Martha Stewart Weddings)

Lauren Conrad is in full prep mode for her upcoming wedding day, and that includes designing the dresses that her bridesmaids will wear.

"The Hills" alum recently launched her own line of bridesmaids dresses. Her Paper Crown clothing line sells 12 different styles, which Conrad and five of her nine bridesmaids modeled in the fall issue of Martha Stewart Weddings.

"In our collection, we're only doing a few dresses that aren't long," Conrad told the magazine. "We're doing full-length, a couple midi, and then we have a couple to-the-knee. We didn't really go shorter than that because it doesn't really feel appropriate, and if that's what you want, then you can always shorten the dress."

The 28-year-old, who is expected to tie the knot with law student William Tell later this year, also dished on how she's getting her bridesmaids ready for her big day.

After asking her besties to be bridesmaids with a specially designed necklace that looks like her engagement ring along with a "will-you-be-my-bridesmaid" card, Conrad let them choose among different shapes and two colors.

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"I don't mind if there are a few girls in the same dress, or if people are all in different ones," she told Martha Stewart. "It's too difficult to take a group of girls and put them in the same color and silhouette; everyone has their own style."

She added, "They're all wearing the same two colors, so it's all the same color scheme. I don't think it needs to look too cohesive. They're all individuals, so it's nice that it doesn't look too uniform."

As for hairstyles on the big day, Conrad is letting her bridesmaids do whatever they want.

But, she admits, when it comes to nails she may need to offer some input.

"I was thinking about doing a gift bag and just including a pale pink or a nude in there," Conrad told the magazine. "I think that's a nice way to suggest, like, 'Here's a pretty color for you.' Yeah, that might actually be a good call because some of my friends will probably have navy or dark nails!"