Little girl sobs with joy after discovering her mom is pregnant

— -- One big sister broke down with tears of joy at the news that her mom was pregnant with another child.

Alicia Capello waited until her daughter, Alexis, 13, was home from a two-week vacation visiting family in Georgia before spilling the beans to her and the family's 4-year-old son Nicholas.

“I had found out around five weeks and we wanted to keep it quiet for a little while until I went to the doctor to make sure everything was OK,” Capello, of New Hampshire, told ABC News. “We decided to tell the kids when [Alexis] came home because we were too excited to keep it from them anymore. I was really anxiously awaiting her coming home.”

Capello and her husband, Anthony Capello, made little goody bags with pink and blue paper, baby-themed candy and T-shirts that read “Biggest 2003” and “Middlest 2012.” At first, Alexis was confused “because she’s always been the biggest,” Capello said of her daughter, who opened her bag first.

But as soon as her younger brother opened his shirt, she realized Nicholas would no longer be the baby in the family. That's when the waterworks started flowing.

The happy parents had her open another bag with a onesie in it. Written across the onesie was: “Littlest 2018.”

“We absolutely expected her to cry and be emotional, but it was definitely really strong,” said Capello. “Her reaction was very genuine. She said afterward she didn’t think we were going to have any more kids, so she was really happy.”

The Capellos don't know yet if they are expecting a boy or girl. If the baby is a girl, the kids already have a middle name picked out for her.

Baby Capello is due next February.