The baby, whose gender has not been made public, was born in London, where Tatum is currently filming the movie Jupiter Ascending, according to the magazine.
The couple, who have been married since 2009, announced that they were expecting a baby in December.
Tatum will next be seen in the action film White House Down, which hits theaters June 28. Dewan-Tatum next stars in the TV series The Witches of East End, which will premiere on Lifetime later this year.
Congratulations to the growing family!