Star qualifications: Longtime TV actor, most famous for "The Mary Tyler Moore Show" and one of its spinoffs, "Rhoda" Pro partner: Tristan MacManus Harper's an old showbiz pro and that work ethic should serve her well. But being realistic, she's 74 years old and is fighting inoperable brain cancer. How does she get through a jive? How does she sell a rumba? Tristan will give it his best shot, but Harper will leave early.
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