Will you be my bridesmaid — and get Botox and a spray tan?

After the band was chosen and the napkins color-coordinated to match her shoes, Kacey Knauer, a bride-to-be, had another critical matter to address: her skin, and the skin of the nine women in her bridal party.

So Knauer, the 35-year-old owner of TempTrends, a staffing agency in Manhattan, invited her nearest and dearest — including her mother and future mother-in-law — for a night out at the TriBeCa MedSpa, replete with mimosas and cupcakes. An aesthetician assessed each woman's face and devised a treatment plan — a quick chemical peel, say, or an injection of a wrinkle-filler. Or maybe, for a bridesmaid with age spots, a series of Fraxel laser treatments over months, allowing for recovery time.

For Knauer, who will be married in December, cosmetic interventions for herself and her entourage are as vital as the centerpieces or food. "If I were 25 or 26 and getting married, a bracelet, necklace or matching earrings would be fine," she said.

But at 35? "Giving them a bracelet isn't as special as spending an evening together. Plus, as you get older, everyone is more conscientious about their skin and appearance," she said. "Giving them something for themselves — as opposed to something that they'll never wear again — is more meaningful."

And let's not forget the pictures of college roommates-turned-bridesmaids quickly posted to Facebook. It is no longer sufficient to hire a hairstylist and makeup artist to be on hand the day of. Instead, bridal parties are indulging in dermal fillers and tooth-whitening months before the Big Day.

Some brides pick up the tab for their attendants, replacing the pillbox inscribed with the wedding date with a well-earned squirt between the eyes. In other cases, bridesmaids — who may quietly seethe about unflattering dresses — are surprisingly willing to pay for cosmetic enhancements. "Most women, when they come in here, they want it," said Camille Meyer, the owner of TriBeCa MedSpa. "They know they're aging."

Beyond friendship?

For Karen Hohenstein, who held her party at the Tiffani Kim Institute Medical Wellness Spa in Chicago, persuading her friends was as smooth as a Botoxed forehead. "It wasn't me saying, 'Hey, we all could use a little something,' " she said. "It was, 'I want to do this,' and a couple of people said, 'I do, too.' "

But for every accommodating pal, there's another who feels going under the knife is beyond the duty of bridesmaid. Becky Lee, 39, a Manhattan photographer, declined when a friend asked her — and five other attendants — to have their breasts enhanced. "We're all Asian and didn't have a whole lot of cleavage, and she found a doctor in L.A. who was willing to do four for the price of two," said Lee, who wore a push-up bra instead.

Not for nothing are some maids known as slaves of honor, but this kind of cajoling is a recent development on the wedding front.

Marie Scalogna-Watkinson, the founder of Spa Chicks on-the-Go, a mobile spa, said she receives five to seven calls a month from brides seeking Botox or Restylane for their bridesmaids. Five years ago, collective makeovers were unheard of, she said.

Dr. Fardad Forouzanpour, a cosmetic surgeon in Beverly Hills, Calif., said his business has increased more than 40 percent since he began offering what he calls Bridal Beauty Buffets in 2006.

A growing trend

In the past two years, bridal party tuneups have increased roughly 25 percent, estimated Susie Ellis, the president of SpaFinder.com, a site that lists 4,500 spas worldwide.

Just as timing matters when it comes to securing a hall, it's best that brides-to-be don't delay scheduling appointments, aestheticians and doctors say. "You wouldn't get a cut and color the week before," said Dr. Jessica Wu, a dermatologist in Beverly Hills who advises coming in three to six months before the big day. "We do a trial run of Botox about four months ahead of time. Then, two weeks before the wedding, we do that last treatment."

Meyer of TriBeCa MedSpa suggests that a bride contact her the minute the question is popped. "Brides really appreciate the fact that we put everything in a regimented schedule for them," she said. Since February 2007, she has staged more than 30 bridesmaid parties and has 18 planned so far this year. "If you have to do eight treatments, six weeks apart, that could take up to a year," she said.

Fraxel laser could also set you back $1,200 a session, which even without the economic downturn, amounts to quite a bit. These days, Robyn Bomar, an event planner in Destin, Fla., overhears brides doing cost-benefit analyses. "They will never choose Botox over a great dress, but they will say 'Maybe I'll have a buffet over a sit-down at the rehearsal dinner,' " she said. Or: "I'll spend the money on Botox rather than lunch.' "

Diplomacy matters

A bride's request that you whiten your grayish teeth can strain a relationship. Samantha Goldberg, a wedding planner in Chester, N.J., recalled a bride who asked her attendants to get professionally spray-tanned for a Hawaiian-theme reception.

Alas, two women were claustrophobic and couldn't bear standing in a tanning capsule. "They asked the bride if they could use regular tanning cream from a salon," Goldberg said. The bride refused; she wanted everyone to be the same shade. The women ultimately declined to be bridesmaids. "Friendships of 20-plus years gone over a spray tan?" Goldberg said. "Sad!"

And how does a bride break it to a mother-in-law that she'd love her crow's feet to be frozen into submission? Very delicately.

"My mother is in her 60s. She's been talking about it for so long, so I said 'Let's do it,' " said Stacey Berlin, 29, a marketing consultant, who is having a party at Aquamedica Day Spa in Long Branch, N.J.

It was trickier with her future mother-in-law. "To her," Berlin said, "I said it as a joke: 'You should do Botox for the wedding!' She giggled, and then I said, 'I'm serious. It's exactly what you need to freshen up.' At first she kind of laughed it off, but the more we talked about it and I told her my mom was going to do it, she said 'OK.' "