Controversial 'twerking' star Miley Cyrus is to appear on the X Factor, but has been warned to keep her act clean.

The 20-year-old singer caused outrage with her X-rated moves and scantily clad outfit at the MTV Video Music Awards last month.

Her twerking - gyrating against fellow performer Robin Thicke in an overtly sexual manner - as well as being provocative with a foam finger prop, caused family groups across the United States to howl in protest and horror.

However, the star was untroubled by the backlash, saying: "I knew I was making history."

The We Can't Stop singer defended herself, explaining she had worn the outfit at other events. "I think people are so much raunchier than I am. I feel like I'm so tame.

"We wore it at [the Billboard Awards] and Britain's Got Talent said they wanted exactly the same. So I thought I'd wear the outfit in black."

Although bosses at the UK talent show are keen to give the popular star a TV spot, they have told Cyrus not to repeat her raunchy performance.

"X Factor never miss an opportunity to exploit a situation so the moment Miley put on THAT routine at the VMA's, producers put the wheels in motion to try to sign her up," a TV insider told The Sun.

"But they can't have her doing anything so raunchy on a Sunday night. They want to be edgy but at the end of the day The X Factor is a family show and before the watershed."

A source told MSN: "Miley is one of the biggest stars around at the moment and she's a great booking for the show.

But after her performance at the VMAs and all the controversy surrounding it, the producers have been nervous about what she might be planning as we can't have anything X-rated given that we're a family show. We will have to make sure she keeps it clean."

An unexpected critic of twerking is One Direction's Harry Styles. He was asked by Moviefone about the recent twerking trend, and although he didn't mention Miley by name, he did give it the thumbs down.

"I think it's quite inappropriate," Harry says of twerking. "Especially for the age groups it's aimed at.

"I think it's, you know, promoting promiscuity," added the pin-up from the boy band, whose recent flings have included Cara Delevigne, Taylor Swift and Caroline Flack.

Watch Miley Cyrus twerking at the MTV Video Music Awards 2013