These twin 21-month-old babies sure have some smooth moves.

Eliana and Evan's favorite toy is their musical monkey that plays Ke$ha's hit song "Tik Tok" when they press its hands.

"You push its little hands and it plays that Ke$ha song, and they love it," the twins' mother, Heidi Boan, told ABCNews.com. "They just kept dancing away to it."

The YouTube video of the babies bouncing to the beat has more than 20,000 views.

"I'm just glad everyone is having fun with it," Boan said.

The babies apparently love music and dance every chance they get.

"It's one of their favorite things to do," said Boan. "We do music class once a week. They get to express themselves that way. In the car I always have pop music going and they will sit side by side with their sunglasses on and just pop their finger in the air in unison, and they both have a good little beat."

Boan never expected the video to get so much attention but says her babies "really respond to music." They enjoy it so much it's become "sort of their deal."