Allison Williams' wedding was ''stunning''.

The 'Girls' actress married CollegeHumor co-founder Ricky Van Veen in a star-studded ceremony at the luxury Brush Creek Ranch in Saratoga, Wyoming, on Saturday (19.09.15) and one guest says the serene wedding was beautiful.

A source told PEOPLE.com: ''The magical setting featured a small creek and spectacular views. It was a stunning ceremony.

''Guests arrived to gorgeous weather. On Friday, everyone enjoyed the ranch life and did a variety of activities organised by the couple. They had a rehearsal dinner Friday night at the ranch.''

Guests at the wedding included Allison's father Brian Williams, who gave her away, her 'Girls' co-stars Lena Dunham, Jemima Kirke and Zosia Mamet, Katy Perry, John Mayer, Seth Meyers and Bruce Springsteen.

Hollywood A-lister Tom Hanks officiated the nuptials while his wife Rita Wilson, who plays Allison's mother on the hit HBO comedy, was also in attendance.

Allison, 27, and Ricky, 34, got engaged in February 2014 and the actress admitted at the time the proposal was a ''total surprise''.

She said: ''I was completely surprised. A total surprise, the best kind of surprise.''