LOS ANGELES (Reuters) – Grammy performers have been told to cover up at Sunday’s big music awards show, and keep their buttocks, nipples and genitals under wraps. Their politics can’t show either.

In a “wardrobe advisory,” broadcaster CBS also asked musicians and audience members likely to appear on camera at the February 10 Grammy Awards ceremony to avoid wearing brand names on T-shirts as well as clothing with political or activist slogans.

“Please be sure that buttocks and female breasts are adequately covered. Thong type costumes are problematic. Please avoid exposing bare flesh under curves of the buttocks and buttock crack,” said the memo issued by CBS standards and practices department and obtained by entertainment industry website Deadline.com on Wednesday.

“Obscenity or partially seen obscenity on wardrobe is unacceptable for broadcast,” the note added.

The warning follows a lengthy court battle over indecency and obscenity standards on U.S. network television.

CBS, a unit of CBS Corp, was fined $550,000 by the Federal Communications Commission for airing a glimpse of Janet Jackson’s breast when her costume slipped while singing at the Super Bowl half-time show in 2004.

The fine was later thrown out and that decision was upheld by the U.S. Supreme Court in June 2012. CBS has expressed “deep regret” for the incident.

The annual Grammy Awards ceremony honors the best musicians of the year, but is also a major promotional showcase for rising stars and upcoming albums.

In 2010, singer Pink performed upside down in a flesh-colored bodysuit, while Rihanna last year wore a plunging black dress on the red carpet.

Performers at Sunday’s three-hour show in Los Angeles include Rihanna, Justin Timberlake, Maroon 5, Frank Ocean, Alicia Keys and Elton John.