The two singers were in the '90s boy band alongside Joey Fatone, Lance Bass and Chris Kirkpatrick. They were known as much for their wild moves on stage as they were for their funky beats, but J.C. insists he and Justin were the ones who really excelled when it came to the routines.
"I think Justin [Timberlake] and I were probably the best two dancers," he said.
"The fun part about me was I was also acrobatic, so I could do backflips across the stage and things like that - that was one of kind of my things that I brought to the table."
Justin and J.C. were both Mouseketeers on Disney's The Mickey Mouse Club when they were younger, along with other famous faces such as Britney Spears and Christina Aguilera.
Christina is now a mentor on US singing contest The Voice, where a fellow former Mousketeer called Tony Lucca is a contestant. She criticised his performance last week, but J.C. thinks she was just trying to help him.
"I love her. She's absolutely supposed to do her job and express her opinion, and that is definitely her opinion," he told Access Hollywood.
"I think Tony has represented himself magnificently on the show because I don't really just look at Tony as a singer, and [Christina] is thinking in terms of maybe singing, how he sang the song. I'm looking at him as a performer."