All five band members were in attendance to celebrate the vows between Kirkpatrick and Karly Skladany at the Loews resort hotel in Orlando, Fla.
The ‘NSYNC members have seen a lot of each other this year, having reunited in August at MTV’s Video Music Awards.
Timberlake, 32, and Biel, 31, kept it simple in basic black, Biel wearing natural makeup and allowing her soft waves to fall around her shoulders.
The singer has been vocal about how happy his own union has made him.
“Every once in a while, I can catch a glimpse of her when she doesn’t see me looking. I have this moment where I’m like, ‘If you never make a good decision – if you only make bad decisions – for the rest of your life, you made one really good decision,’ ” he said.