The fight will be Dantas' first since Aug. 25, when he was knocked out in the first round by Tyson Nam during a non-Bellator promoted event in Brazil.
Despite the setback, Dantas remains confident and eager to make his first title defense against Galvao. The two have trained together in their native country of Brazil.
"I feel great and I'm ready to defend my belt," said Dantas, who has a pro mark of 14-3. "It seems like I've been away from the Bellator cage for a while, and I'm ready to face Marcos.
"I consider Marcos a friend, but all that goes away when we step into the cage. I'm going to show the world why I'm the Bellator bantamweight champion."
Galvao (13-5-1) earned the 135-pound title shot Aug. 24 with a second-round knockout of Luis Nogueira in the Bellator Season 6 bantamweight tournament final.
"We've known each other for a long time, but this is our job, and nothing will get in the way of that," Galvao said. "We will shake hands before the fight and we will shake hands after the fight, but it's going to be war when the cage door shuts."
Galvao will step in the cage on a three-fight winning streak.