The couple, who are both 32, "are pleased to announce that they are expecting the birth of their first child next year," the Tatums' representative told People.com Monday.
The baby's gender and anticipated birth date were not immediately reported.
Dewan-Tatum is a cast member of TV's "American Horror Story: Asylum."
Channing Tatum is People magazine's current Sexiest Man Alive titleholder. His film credits include "Magic Mike" and "21 Jump Street." The couple married in 2009.