The former 'NSYNC singer, 42, tied the knot with his fiancée Karly Skladany at the Loews resort hotel in Orlando, Fla., on Saturday, PEOPLE has confirmed.
All five 'NSYNC members were there to celebrate with the bride and groom: Justin Timberlake, JC Chasez, Joey Fatone and Lance Bass.
Jessica Biel, who is married to Timberlake, also attended, PEOPLE confirmed.
Kirkpatrick and Skladany have been dating for more than three years and, last October, the singer revealed exclusively to PEOPLE how he popped the question to the then-28-year-old marketing rep during a pre-planned birthday trip to Italy.
"We had a hotel room at the Isle of Capri, overlooking the Mediterranean," Kirkpatrick said at the time.
"It was one of the most beautiful places I've ever been. And it hit me: I wanted to propose to Karly. So I ran to a jewelry store, found the perfect ring and bought it."
And after calling to get her father's blessing, Kirkpatrick explained how the magical proposal went down.
"We were sitting on the balcony with a bottle of champagne and I put the ring in her glass," he said. "I know it sounds cheesy, but it was romantic. As soon as I asked her, she said, 'It's about time!' And we laughed. It was spur of the moment, but it was absolutely perfect."
Kirkpatrick, who reunited on stage with his former 'NSYNC bandmates at the MTV Video Music Awards on Aug. 25 – looked forward to another 'NSYNC reunion on his big day.
"They're all coming to my wedding, so we'll get to see each other again," he told Rolling Stone in August. "Everything goes back. It's like old times."
Additional reporting by MONICA RIZZO