Drew Barrymore

It's official! Drew Barrymore is a married woman.

A source confirms to Us Weekly that Barrymore, 37, and Will Kopelman, 34 said "I do" on Saturday evening at the actress' Montecito, Calif. estate. The couple, currently expecting their first child together, had their family and closest friends in attendance, including Cameron Diaz, pregnant Reese Witherspoon and her husband Jim Toth, Busy Phillips, Jimmy Fallon and his wife Nancy Juvonen.

For the Jewish ceremony -- complete with a custom-made chuppah and performed by Kopelman's rabbi -- the Big Miracle star wore a Chanel gown. (Art consultant Kopelman's father, Arie Kopelman, is the former CEO of Chanel.) Barrymore attended her final dress fitting in Beverly Hills on Thursday with the help of Diaz, 39, her best friend and costar in 2000's Charlie's Angles. "Drew has been leaning on Cameron a lot," an insider told Us. "Cameron has been very involved."

As designed by Gazebo Flowers, floral arrangements included "hydrangeas, small irises, cream and pink roses and lavender lilies," according to another source.

This is Barrymore's third marriage. The former child star married Welsh bar owner Jeremy Thomas in March 1994 -- only to split one month later. Her second marriage, was to comic Tom Green in July 2001. Green filed for divorce that December.

Barrymore and Kopelman briefly dated in 2010 and reunited in February 2011. Kopelman proposed in December 2011 during the holidays in Sun Valley, Idaho. Barrymore has yet to confirm her pregnancy, but has been proudly showing her growing baby bump. A pal told Us, Barrymore decided on a June wedding becaues she wanted "to get married before the baby comes, but doesn't want to be huge."

"Drew has found a family that she wants to be a part of, for so long she had the fun friends and career success but always wanted to be part of a close family, like Will's," says an insider.

The Wedding Singer star told Ellen DeGeneres she's in love with Kopelman's entire family. "He has this incredible family," Barrymore gushed on Feb. 1. "I am as in love with his family as I am with him. Which is an extraordinary sort of gift. You never take that for granted...It really is an absolute blessing. I feel very lucky. They’re incredible people."