Television network CBS has requested stars not to show too much flesh while attending this year's Grammy Awards.
According to Deadline Hollywood, a memo from CBS's Standards and Practices department distributed to guests warned: "Please be sure that buttocks and female breasts are adequately covered.
"Thong type costumes are problematic. Please avoid exposing bare fleshy under curves of the buttocks and buttock crack," it added.
The letter continued: "Bare sides or under curvature of the breasts is also problematic. Please avoid sheer see-through clothing that could possibly expose female breast nipples."
CBS broadcast the infamous 2004 Super Bowl half-time show that included what became known as Janet Jackson's 'wardrobe malfunction'.
At the end of her performance her breast was deliberately exposed by singer Justin Timberlake, leading to the media watchdog group Parents Television Council announcing their members would file indecency complaints.
The network was initially fined by the Federal Communications Commission , though the fine was later overturned.
Representatives for CBS and the Recording Academy declined to comment on the leaked letter.
Elton John, Taylor Swift and Mumford & Sons are among a host of stars to take the stage at the 55th annual Grammy Awards at Los Angeles' Staples Centre on Sunday.