Kelly Clarkson's gets surprised by Kids Onstage at Las Vegas Show

Kelly Clarkson got an onstage surprise at her Las Vegas show.

At her most recent residency show in Las Vegas, Kelly Clarkson was accompanied by two unexpected guests: her children.

The singer's children River Rose, 9, and Remington "Remy" Alexander, 7, who she had with her ex-husband Brandon Blackstock, joined their mother onstage individually during her performance on August 18 at the Bakkt Theater at the Planet Hollywood Las Vegas Resort & Casino.

A duet of "Heartbeat Song," a 2015 song that incorporates the sound of the child's heartbeat captured when the singer was pregnant with her, was performed by the Kelly Clarkson Show host and her daughter. As seen in a fan's video, the pop diva and River hugged each other before and after their performance.

"You look gorgeous," Kelly praised her daughter, who fashioned a white pinstriped dress. "You did amazing. I love you. I'll see you in a little bit."

Remy performed a dance routine while his mother sang "Whole Lotta Woman," the song he chose.

"My son, he is 7 years old. He picked the coolest song for a dude to pick," Kelly addressed to the crowd, as per another fan's video. "I was like, ‘He was destined for greatness just for loving this song alone.'"

"Are you ready to dance?" Kelly asked her son as he appeared on stage.

"I told him, he was like, 'There's gonna be a lot of people,'" the singer told everyone, "and I was like, 'No, we have dances all the time in our house."

Kelly posted a picture of River and Remy backstage during the event the following day.

"Both of my kiddos backstage getting ready to join me on stage in Vegas," she wrote on her Aug. 19 Instagram post. "Nothing will ever be as cool and amazing as these two little humans that will always have my whole heart."