Johnston, who has a child with Sarah Palin's daughter Bristol Palin, confirmed last month that Oglesby is pregnant.
The couple, who have been dating since 2010, have now told Inside Edition that they are having a baby girl.
Oglesby revealed that they plan to name their daughter Breeze Beretta, and confirmed that "Beretta" comes from the gun of the same name.
She also revealed that she had never heard of Johnston before they began dating, while Johnston explained that having a baby with Oglesby will be different from having his son with Palin.
"I'm actually in love, not doing it just because we had a kid together," he explained, adding that there is no question that he wants to spend the rest of his life with Oglesby.
"I couldn't picture it any other way," Oglesby agreed.
Recent reports claimed that Johnston owes Palin thousands of dollars in child support.
Watch Levi Johnston and Sunny Oglesby speaking on Inside Edition below: