Cameron Diaz Can't Stop Smiling After Her Sexy Sleepover With Benji Madden!

Someone's in a VERY good mood!

On Friday night new couple Cameron Diaz and Benji Madden had a sleepover at her Los Angeles home, and on Saturday morning we caught her dropping him off at the Montage hotel in Beverly Hills. After that she picked up some goodies at Whole Foods, and she couldn't stop smiling as she pushed her cart around the grocery store!

X17online broke the news yesterday morning that the duo have been dating for about a month now. Nicole Richie was the one who introduced the two, and a source tells X17online exclusively, "Cameron is pretty into him ... she likes the bad boys! But the thing is, Benji's actually a really nice guy. They've been having fun together, making sure it doesn't get too serious too fast."

Here's a peek at Benji heading in to the hotel after hopping out of Cameron's Tesla: