Nicole Richie and Joel Madden were spotted checking out the Eco Mom event at a Hollywood Hills home, on March 12.
The stylish mom-to-be chose a beautiful floral printed white frock and accessorized with flat gladiator sandals and her Balenciaga First small classique bag in indigo.
Earlier this week, Joel celebrated his 30th birthday with a private party at the Sunset Tower Hotel, organized by Nicole.
"There was a lot of laughing and even some speeches. Nicole and Joel were nestled in the center of the big group and they looked as happy as they could be to be celebrating with their friends. They were beaming in the soft terrace lighting", an eyewitness told press.