The guests in attendance included Jimmy Fallon and wife Nancy Juvonen, Busy Philips and her husband, and best friend Cameron Diaz.
Barrymore, who is pregnant with her first child with Kopelman, held their rehearsal dinner in a garden at San Ysdiro Ranch. A source told Us Weekly that the hubby-to-be looked "happy, relaxed and calm" as he arrived to the dinner wearing a dark, tailored suit.
"He looked very handsome and was smiling the entire time he walked toward the rehearsal dinner area," the source said.
Fellow "Charlie's Angels" co-star Cameron Diaz has been by the bride's side throughout the wedding planning. On Wednesday, Diaz joined Barrymore for her final dress fitting in Beverly Hills.
"Drew has been leaning on Cameron a lot," an insider told Us. "Cameron has been very involved."
The big day has arrived! Actress Drew Barrymore and art consultant Will Kopelman were married at Barrymore's stunning $5.7 million estate in Montecito, CA on Saturday, reports People.