Karl Lagerfeld and Drew Barrymore Credit: Venturelli/WireImage.com; Michael Kovac/Getty

Even Chanel's famously icy creative director, Karl Lagerfeld, couldn't help but gush when talking to Us Weekly about the dress he designed for Drew Barrymore's nuptials to Will Kopelman.

"It was perfect," he told Us at Chanel's Little Black Jacket Exhibit (celebrating his new book) in NYC Wednesday night. "She knew what she wanted . . . and she got it," Lagerfeld, 78, shared of the white, pleated muslin and organza custom creation the Big Miracle star, 37, wore down the aisle.

Lagerfeld admitted designing for an expectant bride presented certain challenges he wasn't used to. "[There was] only so much we could do," he explained. "[But] for someone who is pregnant she looked perfect." (In the end, the German-born designer chose to accentuate Barrymore's waist -- and baby bump -- with a black satin belt, and embroidered the skirt of her dress with feathers and organaza, muslin, and tulle flowers.)

Calling Barrymore a "sweet person," Lagerfeld said he's known her new husband, Will Kopelman, since the art consultant "was a child."

"His father [Arie Kopelman] was the President of Chanel America," Lagerfeld explained to Us. "Will is divine and sweet. They're a good match!"

Barrymore and Kopelman, 34, said "I do" in a Yifat Oren and Stefanie Cove-planned affair on the actress' Montecito, Calif. estate Saturday, in front of 170 guests -- including her godfather Steven Spielberg, Scarlett Johansson, Reese Witherspoon and Jim Toth, Busy Philipps, and Jimmy Fallon.

"When they looked at each other, it was so real," an attendee tells Us of the head-over-heels couple's big day. "I've never seen two people more in love."