"It's a boy!" she shared on the show, Whine Down With Jana Kramer.
The couple learned their baby's sex at a gender reveal party where they opened a pinata to reveal blue confetti.
"My girlfriend Ashley called the doctor once the sex came in and she filled a piñata up with [blue] confetti," Kramer told Us Weekly. "And then when we hit it, we were like, 'Oh!' Like, we were shocked. It was a really nice actual surprise."
Kramer's son will be her second child with husband Mike Caussin — the couple is already parents to daughter Jolie, two.
"I was convinced it was a girl," the One Tree Hill alum said of her second child. "Like, absolutely convinced with how sick I've been and the cravings I've had. I was like, 'OK, I'm definitely having another girl.' And I kind of secretly wanted a girl because I never had a sister, so I always wanted to know what that was like."
While Jolie was present for the gender reveal, Kramer noted that her daughter took a little longer to realize that she will soon have a baby brother.
"She saw the confetti and stuff, but I don't think it really kicked in until she went to the 3-D ultrasound with us," she said. "Now that my belly popped, she's finally getting it. Like, there's a baby in my belly, and I'm like, 'It's your brother!' And she's like, 'Yay!' … I can tell that she is very excited for the boy."
Kramer's baby boy is due in November, and she shared that her husband is determined to do things differently when his son arrives.
"He wants to raise his little boy [with] respect and kind of do the things that he wishes he would have done," Kramer said of Caussin. "He's gonna be such a good dad to a boy. It's gonna be challenging because in this day and age for boys, you don't want to be too hard on them, but you still want them to know it's OK to show emotion and to kind of have that mix."
Photo Credit: Instagram / @kramergirl