Allison Williams and Ricky Van Veen exchanged vows in a star-studded wedding ceremony out West on Saturday, Sept. 19. Credit: Kevin Mazur/Getty Images

Hollywood goes country! Allison Williams married longtime boyfriend Ricky Van Veen in a star-studded ranch wedding out West on Saturday, Sept. 19, a rep exclusively confirms to Us Weekly. And the Girls star’s guest list read like a true who’s who in entertainment.

Williams, 27, and entrepreneur Van Veen, 34, said "I do" in front of a gathering of close family and friends, the rep tells Us.

Guests at the event included Katy Perry, John MayerBruce Springsteen, Bee Shaffer, Andy Cohen, Tom Hanks and his wife, Rita Wilson (who plays Williams’ mother on Girls), and Williams’ costar Lena Dunham.

The top-secret outdoor fete was a weeklong affair. A source tells Us Weekly that guests at the wedding kicked off the weekend on Thursday, Sept. 17, with a casual welcome party, and then celebrated the newlyweds-to-be at a rehearsal dinner on Friday.

On the big day, the Girls star stunned in a handmade couture gown by Oscar de la Renta.

Williams and Van Veen, who co-founded the website College Humor, announced their engagement in February after dating for three years, though the pair kept their wedding plans largely quiet, as the actress’ father, NBC Nightly News anchor Brian Williams, was facing criticism for embellishing news stories. (The newsman later apologized on air for false claims he made about an assignment in Iraq; he was later suspended and subsequently reassigned to MSNBC.)

The brunette stunner has been open about her hopes to start a family in the near future, telling Glamour this past March that she wants to “create a career I can walk away from and become a mom.”

“I’d love to be a mom — and not have to bring my kids into my trailer,” she told the magazine.

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