Courtney Cox-Arquette, Jennifer Aniston, Nicole Richie & Sheryl Crowe Together For The Congo

It was a star-powered night at STK in LA, with Nicole Richie, Demi Moore, Courtney Cox-Arquette, Jennifer Aniston and Sheryl Crow all in attendance at "Stamp Out Violence Against Women and Girls of the Congo."

Mom-to-be Nicole, who showed off her growing baby bump in basic black, explained why she was there to support the cause.

"I'm all about making people aware and showing them what the problem is. It's impossible to turn your back on something like this," she tells People magazine. "It's really hard to complain about anything when you hear the stories of these women and children and their torture."

The event capped off a busy day for Nicole, who wrote on Twitter, "Today I worked, burned my hand, missed a sugar test, wrote a letter to Obama, supported women of the Congo, & met an online porn star...."

Nicole and her boyfriend Joel are expecting baby #2 this summer. Soon-to-be big sister Harlow Winter Kate is 17 months.