NBC has renewed three reality series: veteran The Biggest Loser, the Lisa Kudrow-produced docu  Who Do You Think You Are? and singing competition series The Sing-Off. “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.  “They are each unique, attention-getting shows with terrific producing and talent auspices, and we’re proud to be associated with them.”

The pickup of Biggest Loser was a given. Even though the one-time powerhouse is down this year, it still averages a 3.1/8 in adults 18-49 and 8.3 million viewers to rank as one of NBC’s strongest series. The Sing-Off also was expected to be picked up after a solid limited run in December when it averaged a 3.2/9 in 18-49 and 9.2 million viewers, 28% up from its first season.

The early renewal of Who Do You Think You Are? is a little surprising. The series airs in the low-trafficked Friday 8 PM slot and has averaged 1.4/5  in adults 18-49 and 7.0 million viewers. But according to NBC, the unscripted genealogy show based on a British format is the network’s most watched Friday series so far this season.

Also somewhat surprisingly missing from the pickup announcement is NBC’s reality series Minute to Win It. While it has taken a hit from American Idol recently, the game show has been a solid utility player for the network. Decision on its future is yet to be made but NBC already has enough episodes to take it through the summer and into next season.