Clarkson shares River and 13-month-old son Remy with husband Brandon Blackstock, whom she married in 2013.
Blackstock is dad to Seth and daughter Savannah with his ex-wife, Melissa Ashworth.
"We have a blended family. That's another level of trying to make it work and everyone feeling as equally as loved an important, and then also just having a marriage and having a career," Clarkson told "Entertainment Tonight" in December.
"I am more confident now because of all these things my life entails."
"I have never been more confident as a woman as I am as a mother. The amount of stuff I get done in a day is insane," she said. "I feel like I'm nailing it."
Clarkson previously said in an interview with "The Jenny McCarthy Show" podcast that she and Blackstock are done having children.
She made Blackstock get a vasectomy after she had another difficult pregnancy with Remy.
"It something happens, it's a miracle of God," the star joked.
Clarkson came to fame after winning the first season of "American Idol" in 2002 and is scheduled to serve as a coach on Season 14 of NBC' "The Voice" in early 2018.
She last released the album Piece by Piece in 2015, which includes the singles "Heartbeat Song" and "Invincible."
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