Amy Sedaris, Kim Kardashian and Brian Regan appear on “Late Show with David Letterman” (10:35 p.m., CBS). Earlier this week, ABC announced that Kardashian would join the talent on the new season of “Dancing with the Stars,” beginning Sept. 23.

The ABC press release calls Kardashian a model, actress and a reality TV star. It would be easy to dismiss her as just another ditzy celebrity, but that is not the case. Kardashian’s Wikipedia entry: “Kardashian was little known outside gossip circles until the pornographic home video she had made with then-boyfriend, R&B singer Ray J, was leaked.”

I’m neither a prude nor a moralist nor a censor, but what is she doing on a family-oriented series like “Dancing with the Stars”?

This casting stunt is not only sleazy, it’s dumb. Kardashian’s series on E! reaches a tiny fraction of the audience for “Dancing.” So why is the Disney-owned ABC stinking up its hugely popular franchise? Don’t parents have a hard enough time without Mickey Mouse giving the Tinkerbell Seal of Approval to homemade porn?

¢ I’m always amazed by American pop culture’s ability to take the most difficult material and turn it into “entertainment.” In the 1950s, a new arrangement of “The Three Penny Opera” helped Bobby Darin transform a sinister song about a serial killer into his ring-a-ding show-stopping anthem “Mack the Knife.”

Tonight, the Animal Planet transforms another bleak German import into something for the kiddies. “Grizzly Man Diaries” (8 p.m. and 8:30 p.m., Animal Planet) offers snippets of video from the late naturalist Timothy Treadwell. He spent 13 years bonding with grizzly bears and took thousands of hours of video and more than 10,000 still photographs.

Director Werner Herzog’s acclaimed 2005 documentary “Grizzly Man” profiled Treadwell’s sojourn among the bears in Alaska’s Katmai National Park and preserve. But it also revealed its subject’s showbiz-obsessed past, spasms of rage, obscene rants and the reckless disregard for reason that would eventually get Treadwell and his girlfriend killed by the very bears he celebrated.

Animal Planet’s series avoids this dark side and shows Treadwell’s moments with a mother bear and her babies that he gives cute names, like Emmy and Letterman. But you only have to listen to Treadwell’s Mister-Rogers-on-helium voice to notice that you are in the presence of a very odd duck.

Tonight’s other highlights

Note: Local listings may vary because of preseason NFL coverage.

¢ U.S. Open Tennis (6 p.m., USA).

¢ Josh Duhamel, Kate Bosworth and Topher Grace star in the 2004 comedy “Win a Date With Tad Hamilton” (7 p.m., ABC).

¢ Anne Hathaway stars in the 2004 kids fantasy “Ella Enchanted” (7 p.m., Disney).

¢ “15 Most Shocking Political Sex Scandals”

(7 p.m., E!) takes an “undercover” glance at politics.

¢ A widow’s grief takes its toll on two unwalked dogs on “The Dog Whisperer” (8 p.m., National Geographic).

¢ A fugitive ex-Marine teams up with a dangerous bunch on “Numb3rs” (8 p.m., CBS).

¢ Scheduled on “20/20” (9 p.m., ABC): Internet expert Bill Tancer; Olympic athletes and sponsorships; a repeat report on a controversial film about suicide.