The 32-year-old actor says his first thought on hearing the news was: "'Y'all are messing with me.'"
Tatum's film roles include "Magic Mike" and the upcoming "Foxcatcher."
Other actors who have received the "sexiest" label include George Clooney, Matt Damon, Brad Pitt, Johnny Depp and Ryan Reynolds. Last year's "sexiest man" was Bradley Cooper.
People announced its 2012 list Wednesday.