Drew Barrymore, Will Kopelman Rehearsal Dinner Details

Will Kopelman and Drew Barrymore attend the Natural Resources Defense Council's Ocean Initiative Benefit Hosted By Chanel on June 4, 2011 in Malibu, California.  Steve Granitz/WireImage.com

The big day has arrived!

Drew Barrymore is tying the knot with Will Kopelman Saturday, and Friday night they invited friends and family to join them at a rehearsal dinner in Montecito, Calif.

Expecting their first child, the couple held their rehearsal dinner in a garden at San Ysdiro Ranch. A source tells Us Weekly that Kopelman, 34, looked "happy, relaxed and calm" as he arrived to the dinner around 6:30 p.m. wearing a dark, tailored suit.

"He looked very handsome and was smiling the entire time he walked toward the rehearsal dinner area," the source says.

Among the attendees: Kopelman's sister Jill Kargman, author of The Rock Star in Seat 3A, attended the dinner with her two children, plus Jimmy Fallon and his wife Nancy Juvonen were also in attendance.

The dinner was kept short and sweet, with guests leaving the bash around 8pm. 

According to E! News, the 70 guests were given gifts of Santa Barbara olivies, chocolate truffles and bouquets of lavender in the hotel rooms at the Four Seasons Hotel and San Ysidro Ranch.

Barrymore will become Mrs. Will Kopelman later on Saturday. Her best friend Cameron Diaz, 39, has been by her side through the wedding planning. On May 30, Diaz joined Barrymore for her final wedding dress fitting in Beverly Hills.

"Drew has been leaning on Cameron a lot," an insider tells Us. "Cameron has been very involved."

Sign up now for the Us Weekly newsletter to get breaking celebrity news, hot pics and more delivered straight to your inbox!

Want stories like these delivered straight to your phone? Download the Us Weekly iPhone app now!