JC Chasez — Yes, I Went to the Wedding (Not JT’s Wedding)

EXCLUSIVE

JC Chasez was one of THREE members of *NSYNC who was NOT in attendance at Justin Timberlake‘s wedding this weekend … but he watched two OTHER people say “I Do” … TMZ has learned.

Just like Joey Fatone and Lance Bass … JC didn’t make the trip to Southern Italy to see his former boy-bandmate JT tie the knot to Jessica Biel.

Instead, JC had more important plans — his brother was getting married in Orlando, FL.

We’re told JC had planned to go to his bro’s wedding for over a year  — and had previously informed Justin it was a top priority he just couldn’t miss.

As we previously reported, Joey spent his weekend in L.A. (it’s unclear if he was even invited) … and Lance was at an event in San Diego.

We do know Chris Kirkpatrick WAS in Italy at the time of Justin’s wedding — but we still haven’t seen pics of the singer INSIDE the ceremony.