"Sup everybody……. guess who is gonna be a BIG brother," Aldean captioned his post.
Memphis was born in December after the couple went through a year-long journey to conceive, eventually having their son with the help of in vitro fertilization treatments. They have not said if they went through IVF this time.
The baby will be the second for Kerr Aldean and the fourth for Aldean, who has daughters Kendyl, 10, and Keeley, 15, from his previous marriage to Jessica Aldean.