Washington, Mar 17 : American socialite Paris Hilton and Nicole Richie were seen on a double date on Friday Mar 14.
The two were seen at the Los Angeles opening of identical twin brothers Joel and Benji Madden's first DCMA Collective clothing store.
"It's not the first time we have all hung out," Joel told Usmagazine.com.
"We have obviously known Paris for a long time, and [Nicole and Paris] have known each other for a long time, so it's nothing new," he added.
Joel and Nicole had welcomed their baby daughter, Harlow in January 2008, while Benji and Paris made their romance public late last month.
Paris revealed that the four of them would often get together, however they usually spent their time at home.
"[Nicole and Joel] really don't go out, so we mostly hang out at her mom's house with the baby and watch movies and cook," she added.
Paris has just been going on and on about the store opening, which had attracted The Hills' Audrina Patridge, Pete Wentz and Nicky Hilton and her beau David Katzenberg.
"They are really cute," Paris told US mag of the DCMA collection.
"They work with some of the most amazing graffiti artists to make these really cool T-shirts that no one really has," she added.
When asked the reason for their clothing line being named DCMA, Joel said it represented the place where they came from. "We are from a small town outside Maryland, and we used to go to punk rock shows. This just represents where I'm from: Washington DC and Maryland," he said.