'Are you kidding me?' Watch sisters' sweet reaction to surprise adoption

Reagan and Harper Pruitt broke down in tears when they were told that the little girl in their mother's arms was their new baby sister.

"Are you kidding me?" Harper screams in a video of the sweet reaction.

"She said, 'Your new baby sister,' and my mind blew up," Older sister Reagan told WFAA.

The new baby brings the Pruitt family to seven. Parents Kasi and Shane of Rockwall, Texas, said they feel called by their faith to adopt.

"It's almost like God spoke to her first and then He had to convince me later," Shane said.

After they had Reagan and Harper biologically, the family adopted Titus, who is from Uganda and has cerebral palsy, and 2-year-old Elliott. When they found out about an opportunity for a quick third adoption, they decided to go for it before telling the girls, hence the heartwarming moment caught on camera.

The family said they consider the baby's mother a part of the family.

As for the baby, she has already won over her big sisters.

"They fight over who gets to hold her," Shane said. "They fight over who gets to feed her. They don't fight over who gets to change the diaper. That's when they hand her back."

Read more about this story from WFAA.