Calvin Johnson -- I'm Coming Out Of Retirement ... For 'Dancing With the Stars'

MEGATRON IS BACK ... kinda ... 'cause Calvin Johnson is competing again, wearing his tights again, but this time as a new contestant on "Dancing With the Stars."

ABC just announced the new cast to the world ... making it official that Johnson will be following in the fancy footsteps of gridiron greats like Hines Ward, Emmitt Smith, and Jerry Rice.

Johnson shocked the football world when he retired earlier this year at 30 ... but never fear Detroit fans, you can watch him once again going head to head against Vanilla Ice & Ryan Lochte.