Going into dancing classes with Mia, Casey was surprised by how bad she was on 'Better With You' (Mon., 9:30PM ET on ABC). In a special Monday airing of the series after 'Dancing with the Stars,' fans of ABC's reality competition had a chance to see one of their favorite professional dancers.

Derek Hough took the season off from 'DWTS' to film a movie, so it's a special treat for his fans to get to see him dancing on Monday night right now.

After pretending to be worse than he is on the dance floor to make Mia feel better about her own lack of abilities, she started getting cocky. Finally, after she insulted him one too many times, Casey had enough and turned to Hough.

"I am an expert dancer," he told Mia. He then extended a hand to Hough.

"I have to do this," Casey said. "I can't keep it in anymore." With this, the pair erupted into an impromptu performance that was a lot of fun. Sure, Casey wasn't nearly as good as Hough, but he proved surprisingly adept on his feet.

As for Hough, he proved more than capable of handling the traditional female role in the dance.