In honor of Katie Holmes' recent obsession with boyfriend jeans, I thought I'd post In Style's recap to fashion rules celebrities don't mind breaking.

Rachel Bilson: "Forget the old rules. I love white all year round. It's cooler to wear it when you aren't supposed to."

Rihanna: "The idea of not wearing brown and black together seems so dated. The
other day I wore a black T-shirt, black Nobody jeans, a brown
leopard-print belt by Dolce & Gabbana, and brown Giuseppe Zanotti
shoes, and it looked awesome. And I also love to mix prints."

Ciara: "Combine different materials in your accessories. I wear a lot of different bangles—gold, silver, wood, acrylic. It's fun."

Hilary Duff: "I never do one designer all the way, like an entire Dolce &
Gabbana outfit. It's not practical. It's more fun to mix your street
wear with high fashion." 

There are so many more! Click on the continue reading link to see what the other female celebs said.

Janet Jackson: "Just because a trend happens doesn't mean you should adopt it. Wear what best fits your shape."

Julianne Moore: "I learned at a young age that physicality isn't important. It can be manipulated."

Keira Knightley: "I love blokes' shirts. I bought a plain white men's Prada shirt in Rome."

Marcia Cross: "Some people think wearing powder ages them, but try it anyway. For me it mattes my makeup and blends it well."

Catherine Zeta Jones: "A woman should never wear anything she cannot lose. Why have jewelry in a safe? Stack it on and enjoy!"

What fashion rule are you known for breaking?

Photos by WENN