The celebration was attended by close friends and family and the shower was hosted by producer Leonard Goldberg and his wife Wendy at a private home.
Goldberg produced the "Charlie's Angels" movies with Barrymore and the actress' production partner Nancy Juvonen, reports people.com.
"Barrymore and Kopelman, who shared a kiss before entering the party, are just enjoying talking about wedding plans and are excited for married life," a source said. "She is excited about the wedding, but very laid back. She is definitely not a bridezilla," another source said.