EXCLUSIVE PHOTOS: Jennifer Aniston's Beautiful Backyard Wedding
More than 70 friends and family members were on hand for the occasion; a wooden stage was front and center, with seating for 74 set up around the mansion's sprawling backyard.
The couple's sprawling pad was the perfect spot for the festivities: protected by thick trees and with plenty of space for guests to party.
Party staffers spent the morning setting up, keeping the dance floor covered.
Gotta stock the bar! The couple, known for throwing lavish parties for their friends, had the major wedding bases (flowers, snacks and drinks) covered.
Preparations on the sprawling property began Tuesday, with workers really getting underway by 4:30 p.m. Wednesday.
Further proof? Aside from PEOPLE's confirmation, a pastor was seen arriving on the grounds mid-day.
Another V.I.P. guest – the cake! – is delivered to the couple's home. The colorful confection featured the bride and groom in Muppet form.
"Guests were told it was a birthday party for Justin," says a source. "Jen and Justin wanted to surprise guests and guests were certainly surprised."
"Jen has been very good at keeping her wedding planning secret," a source tells PEOPLE. "Only her closest confidants knew that the party was actually a surprise wedding."
In June, Aniston opened up to PEOPLE about her man, saying, "Justin was the best thing this decade." The year before, she'd said, "He gets better every year."
In 2014, a friend of the couple told PEOPLE, "It's amazing to see how happy Justin makes Jen."
"He's just so beautiful and handsome to me," Aniston once said at a dinner honoring The Leftovers star. "He's just like a lost gem in the sand, and he's just always been there and been brilliant, and now this is just in a different light."
Also happy for the newlyweds: the Internet! Fans took to Twitter to share their serious well-wishes for the stars.
Theroux proposed to the 46-year-old actress – whom he met on the set of Tropic Thunder, which he wrote and appeared in – on his 41st birthday, Aug. 10 2012.
Next week marks the third anniversary of the couple's engagement.
Last November, Aniston joked to Ellen DeGeneres that her guests always assume that her parties will turn out to be her long-awaited wedding. Example: Sacha Baron Cohen and Isla Fisher. "They would show up in beautiful wedding wear," Aniston explained. "Even the 4th of July last year, they showed up, and Sacha was in a powder blue suit, and Isla was in a little cute dress. And we were like, 'Guys, it's the 4th of July. We're in cutoffs and eating hot dogs. We will actually let you know!' "
Cheers to Mr. and Mrs. Theroux!