"Dancing" has been among the biggest hits of the season, with Tuesday night's broadcast capturing a 22.5 million viewers for the hourlong competition that began at 8:30 p.m. EST.
In next week's final round, Lopez, with partner Karina Smirnoff, and Smith, with partner Cheryl Burke, get to perform their favorite three dances.
"Mario is a very talented individual," Smith said.
Judge Bruno Tonioli has described Smith, an NFL MVP, as a "great American wonder."