Cameron Diaz and Nicole Richie go on a Valentine's Day Double-Date with The Madden Brothers

Cameron Diaz and husband Benji Madden were seen having a Valentine's Day dinner with Nicole Ritchie and her husband Joel Madden at Il Restorante Di Giorgio Baldi's in Santa Monica, California. They arrived 9:00 pm, all four in all-black ensembles.

Cameron, 42, came in a flowing black dress, accented with a statement necklace and a pair of golden heels. Nicole, 33, arrived wearing a black top with matching trousers, over which she has on a patterned brown full-length coat with faux fur-lined collar and cuffs, complemented with a pair of patent black Oxford shoes and accented by a chunky gold necklace.

Benji, 35, has a black ribbed shirt on with matching blazer, leather trousers and hi-top Converse trainers, while his twin brother Joel came in a black button-down shirt with matching trousers and black Vans sneakers.

Quoting an unnamed source, People magazine wrote: "She [Cameron] and Benji looked very happy. They had a fun, three-hour dinner with Nicole and her husband. They didn't even look at the menu and instead ordered their favorites, including ravioli agnolotti with white truffle, lobster and Spigola." The pair of couples, according to the celebrity news provider, didn't drink any alcohol, but instead capped off the night with a strawberry dessert.

An eyewitness reportedly told US Weekly: "Cameron was having a great time, laughing very loudly at everything Benji said. She was full of energy and was a chatterbox the entire meal. She was whispering to Nicole and laughing, and then looking over at Benji and Joel and laughing. The four of them seem to be super close."

Saturday's date was Cameron's and Benji's first Valentine Day together since they got married on January 5 in front of their 127 guests at the actress' Beverly Hills estate. They were married after a 17-day engagement. They were introduced to each other seven months ago by now sister-in-law Nicole.

Nicole has been married to Benji's brother Joel since December 11, 2010. They have two children together, 6-year-old daughter Harlow and 5-year-old son Sparrow.

Joel and Benji make up The Madden Brothers, a pop rock collaboration separate from their rock band Good Charlotte. To date, the twins have released a total of five studio albums, two live albums, two extended plays, twenty singles, seventeen music videos and three music DVDs.