Donny Osmond and Kym Johnson will be dancing the samba, jitterbug and tango when they compete to make it into the finals on tonight's "Dancing with the Stars."

There are four couples left and only three will go into the finals, but Donny is determined to make it into the finals because he wants to make it just as far as -- if not further than -- sister Marie did on her season. That said, three dances isn't easy -- especially since he is dancing with a broken toe.

"Both Marie and I are very competitive people," he tells ET. "I set out to win the trophy. If you compare the two of us, I would say I am more competitive. She would disagree."

Kym has pushed Donny hard this week, joking that she used a pole to keep him in line, but the truth is she has been very innovative, using a hula hoop to help him improve his posture and his hold.

As for teaching him multiple new dances, Kym says, "I normally go with the more difficult dance first. We started with the tango. By Saturday, we have both dances down and we start to clean it. The weekend is cleaning and polishing it."

Luckily for Donny and Kym, they never fell into the bottom two, so their third dance -- the jitterbug -- will be the dance they were going to have to do if they had to take part in the Dance Off.

"Of all these three dances, the one that scares me the most is all three of them," Donny says, laughing. "Because they all three have to be perfect. They have to be the best we can do. It is down to the wire. There is no fooling around. There is no room for mistakes."

One fun thing about the samba for Donny is that he and Kym will be dancing to his first No. 1 record: "One Bad Apple."

"It was difficult choreographing the routine because it is Donny's song, so I felt a lot of pressure to make it really good and showcase Donny," Kym tells ET. "He has a solo in it. All the celebrities have to do a 15-second solo in the semi-finals."

"Dancing with the Stars" airs Mondays and Tuesdays on ABC.