Here's one case where Bell Biv DeVoe broke their own rule -- and totally trusted a big butt and a smile ... because they were some of the VIPs at Serena Williams' wedding!!
It all went down in New Orleans on Thursday night -- where huge stars like Kelly Rowland, Ciara, La La Anthony, Boris Kodjoe, Kim Kardashian and Caroline Wozniacki partied until the early morning.
And here's the first look at Serena's dress ...
As we previously reported, Serena and her (now) husband Alexis Ohanian went all out on the party -- and due to the fact the guys from BBD were there and wearing matching clothing ... we're guessing they performed live.
The decorations were tennis-themed -- the guest seating placards were in the shape of Wimbledon and U.S. Open trophies. Pretty damn awesome.
We'll have more on this throughout the day-- so keep checking back!
Mazel!