Kevin quit in 2006 to pursue an acting career and start his family. There's always gonna be an open door for him to come back to the group, but at least he came back recently for the Oprah show special last week. He also was a part of the encore act for the Unbreakable Tour in 2008 when it was in Hollywood.

Backstreet Backstage - Q&A with the Reunited Fivesome - Oprah.com

And Kevin is so not old. Friggen Nick is 30 now. Brian's 35...I dunno how old the other guys are.