03/19/2012 at 04:00 AM EDT
is expecting a baby girl
– and her family and friends have already started helping her celebrate!
On Sunday afternoon, her nearest and dearest gathered in Los Angeles for a baby shower organized by celebrity event planner Mindy Weiss.
wore her hair down with soft braids around her face and sported a light blue dress that showed off her pregnant belly
. She was joined by Jessica Alba
and sister Ashlee
. And when Ashlee arrived with son Bronx, Jessica greeted them outside the party.
"Jessica looked pretty and very happy," says an eyewitness.
Adds a friend: "She's so excited to be a mom. She can't wait to meet her little girl."
Reporting by ULRICA WIHLBORG