Nick Carter joins 'Dancing with the Stars' Season 21

CEBU, Philippines - Backstreet's back all right!

"Dancing with the Stars" has yet to officially announce the celebrity cast for its upcoming 21st season soon, but ABC has finally made it official and announced Backstreet Boys member Nick Carter will be competing for the mirrorball trophy when the ABC reality hit returns on September. E! News previously reported Carter was being courted by the dancing reality series.

The former boy bander took to Twitter to share his excitement, posting "You ain't seen nothing yet."

Though they've performed on the show before, Carter is actually the first member of BSB to ever compete on DWTS. But Carter won't be the first member of his family to join the show as his little brother Aaron Carter was part of the cast in season nine, when he was paired with Karina Smirnoff.

DWTS will officially announce its cast of celebrities for season 21 in early September on Good Morning America. But we can already rule out one major celebrity who will not be competing: Caitlyn Jenner, as former champ Alfonso Ribeiro revealed to E! News that the "I Am Cait" star turned the opportunity down.  (FREEMAN)