Sources close to the situation tell Radar Online that the Americal Idol winner and her husband of eight months have just finished their baby girl's nursery in the pair's Nashville, Tenn. home.
"They are beyond excited over this baby. Kelly is just busting with joy and can't wait to hold her," the insider said. "They've got the nursery all together and now it's just a waiting game."
The 32-year-old singer announced she was expecting a baby girl in January, two months after she predicted the baby's gender on Twitter.
Clarkson's announcement came almost two months after a woman stepped forward in December to claim she and Blackstock had had an affair.
"We haven't slept together," the unidentified woman said at the time, "but we've been intimate in other ways. I really hope his wife keeps her eye on him because he's not the great man she thinks he is."
Clarkson is due to give birth on June 18. The child would be the first for the singer and the third for Blackstock who has two kids from a previous marriage.