"Alternative series such as these three bona fide hits are important not only to their loyal audiences but also as strong components of the NBC schedule," NBC Entertainment Chairman Bob Greenblatt said in a statement. "They are each unique, attention-getting shows with terrific producing and talent auspices, and we're proud to be associated with them."
The Biggest Loser's tenth season averaged 8.3 million viewers in the fall and 9 million viewers this winter. The Sing-Off averaged 9.2 million viewers last season, up 27 percent over the previous year.
Who Do You Think You Are? — which will soon feature Sex and the City's Kim Cattrall, Country Strong's Gwyneth Paltrow and Boardwalk Empire's Steve Buscemi — averaged 7.0 million viewers in the first two weeks of its second season.