Lachey, who has danced on Broadway, also found the rehearsals surprisingly grueling.
"I thought it would be a couple of days a week, a couple of hours' worth of rehearsal, and then you go and do the show. … It's been seven days a week -- a minimum of four hours of rehearsal a day," he said.
Some of the competitors are quick to point out that Keibler's dance experience gives her an advantage in the competition. But Keibler insists that moving and swaying with a dance partner is far tougher than the routines she used to perform.
"We're all waking up in the middle of the night and thinking about the dances. And even Jerry Rice came up to me. He's like, "Are you like thinking about the jive at 4 in the morning?' I'm like I know. We're having nightmares about this stuff," she said.
Amid the frenzy, there is still camaraderie between the competitors.
Host Tom Bergeron admits the dancers' personal appeal to viewers is nearly as important as their footwork.
"It's half dance contest, half popularity contest. If it was all dance, it would be on PBS," he said.
That's why each of the dance teams pleads with its fans to vote. On Sunday night, we'll learn who rallied enough public support to bring home this season's trophy.