Watch CBSN Live

First look at Allison Williams' custom Oscar de la Renta wedding gown

All eyes were certainly on the bride in this stunning gown.

Actress Allison Williams tied the knot with CollegeHumor co-founder Ricky Van Veen on Saturday in a secret ceremony at Brush Creek Ranch in Saratoga, Wyoming, ET confirmed. Only a few hours after the "I dos," the "Girls" star shared an Instagram pic of her gorgeous custom Oscar de la Renta wedding dress.

Williams, 27, looks incredible in the image, as she's seen walking hand-in-hand with her groom during their country wedding.

9.19.15 Dress by @oscarprgirl Photo by @christianothstudio

A photo posted by Allison Williams (@aw) on

The wedding included a slew of celebrity guests. Stars included "Girls" creator Lena Dunham, Katy Perry, John Mayer, Bruce Springsteen, Bee Shaffer, Andy Cohen. Tom Hanks officiated the wedding while his wife Rita Wilson -- who played Williams' mother on the acclaimed HBO comedy -- watched from the audience. Also expected were Seth Meyers and wife Alexi Ashe, Diane von Furstenberg and Williams' co-star Zosia Mamet, who was spotted arriving at the Denver airport with boyfriend Evan Jonigkeit on Friday.

Adding to the star power, Katy Perry performed for the couple while reportedly getting cuddly with John Mayer after the ceremony.

This is the first marriage for both Williams and Van Veen, who have been dating since 2011 after meeting through mutual friends. They got engaged in February 2014.

Go inside Williams' wedding, below:

View CBS News In