The All New Mickey Mouse Club ran from 1989 to 1994 and ran seven different seasons.
J.C. Chasez was on the Mickey Mouse Club from Season Four to Season Seven (the last season). J.C. was still a teenager when he was in the MMC. By Season Six, he met up with future bandmate Justin Timberlake.
Justin Timberlake was on the Mickey Mouse Club from Season Six to Season Seven. Justin was 13 when he started on MMC. This is where Justin met up with J.C. who would be his bandmate in N'Sync which started in 1995! =)
