The couple, who exchanged vows in front of more than 70 family members and friends on Wednesday at their Bel Air, California, home, successfully kept the affair a secret – and they did it without leaving their own backyard.
"Guests were told it was a birthday party for Justin. Jen and Justin wanted to surprise guests, and guests were certainly surprised," a source tells PEOPLE. "Jen has been very good at keeping her wedding planning secret. Only her closest confidants knew that the party was actually a surprise wedding."
Here's how Aniston, 46, and Theroux, 44, pulled it off after a three-year engagement that kept everyone guessing:
1. They kept working.
Theroux appeared at the 2015 Summer TCA Tour on July 30 to promote his HBO series The Leftovers, while Aniston is set to film her role in the upcoming Garry Marshall ensemble comedy Mother's Day later this month in Atlanta. Because two people who are busy with work are clearly not in the midst of last-minute wedding prep, right?
2. They always throw a party this time of year.
With Theroux's birthday on Aug. 10 – also their third engagement anniversary – the couple used their annual celebration as a cover for the big day. Aniston even joked that their famous friends kept assuming that "party" was code for "secret wedding." In a November interview with Ellen DeGeneres, Aniston said that pals like Sacha Baron Cohen and Isla Fisher "would show up in beautiful wedding wear. Even the Fourth 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 Fourth of July. We're in cutoffs and eating hot dogs. We will actually let you know!' "
3. They kept the party prep under wraps.
According to TMZ, a giant shed was built on the couple's property during the past week to conceal all the furniture and party supplies, and no parking was allowed near the property.
4. They swore their friends to secrecy.
Even chatty pals like Chelsea Handler and Howard Stern have gone dark about the festivities, and other friends were cagey when reached by PEOPLE yesterday.
5. They waited everyone out.
After three years and endless speculation, it seemed the pair were more than happy to settle into a long engagement. What better time to pull off a wedding heist than when you've lulled everyone into thinking you're not in a rush? The patience paid off!