See Allison Williams's Gorgeous Ranch Wedding

Allison Williams stunned when she tied the knot with Ricky Van Veen in Saratoga, WY, on Saturday. The actress wore a beautiful Oscar de la Renta gown for her big day, and her famous dad, Brian Williams, walked her down the aisle. Tom Hanks officiated the ceremony, and his wife, Rita Wilson — who plays Allison's mom on Girls — was also in attendance.

The star-studded guest list included Katy Perry and John Mayer, who held hands during the ceremony, plus Allison's Girls costars Lena Dunham, Zosia Mamet, and Jemima Kirke. Also in attendance were Mindy Kaling, Bruce Springsteen, Diane Von Furstenberg, Seth Meyers, and Andy Cohen. Keep reading to check out stars' arrivals plus pictures of the beautiful ceremony, then see more of the year's most memorable celebrity weddings!

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Katy Perry and John Mayer stayed close while watching the ceremony.

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Lena Dunham and Jemima Kirke sat behind Katy Perry and John Mayer.

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Tom Hanks officiated the couple's ranch ceremony.

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Katy Perry took the mic during the ceremony.

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The star-studded guest list included designer Diane von Furstenberg.

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Allison's Girls costars Lena Dunham and Jemima Kirke attended the ceremony.

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Katy Perry was all smiles when she arrived.

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John Mayer kept it casual for his arrival.

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Rita Wilson attended the ceremony, which was officiated by her husband, Tom Hanks.

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Diane von Furstenberg was among the famous guests.

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Rita Wilson was spotted alongside John Mayer.

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Seth Meyers was seen arriving with the other guests.