Rihanna's friends are worried Chris Brown could "kill her".

The 21-year-old singer has decided to take back Chris - who has been charged with felony assault and making criminal threats after he allegedly beat her - but those close to her are concerned for her safety after hearing the couple's vicious rows.

One friend told In Touch Weekly magazine: "We have heard him yelling and getting so angry with her since the whole thing went down. We are all scared for her and think he could even kill her."

Chris is accused to punching, biting and choking Rihanna until she was unconscious in his silver Lamborghini. If convicted he faces over four years in prison.

The friend added: "After Chris was arrested she admitted this was not the first physical attack. She said it's been going on for months and it has gotten worse."

It was recently reported Rihanna and Chris, 19, are recording a duet together in Santa Monica with producer Polow Da Don.

Although the name of the song has not been released, it is about a relationship.

A source said: "The theme is about being stronger and growing stronger in a relationship. The song was originally created for Rihanna before the fight.

However, it wasn't initially slated for Chris to be on the song.

"The funny thing is, the song expresses the emotions that both Chris and Rihanna are feeling at this moment - facing challenges and overcoming the ups and downs of a relationship in which you become stronger."

Meanwhile, Chris has withdrawn his name from the nominations at the Nickelodeon Kids' Choice Awards.

The singer was up for Favourite Male Singer and Favourite Song for 'Kiss Kiss' but despite an online petition - which was signed by more than 5,000 people - calling for his removal the children's TV network had refused to do so.

Chris' representative said in a statement: "Chris very much appreciates the support of his fans and the honour they have paid him in the way of nominations. Unfortunately, the controversy surrounding the incident last month has shifted the focus from the music to whether he should be allowed to be among those nominated.

"While Chris would like to speak to his fans directly about this and other issues, pending legal proceedings preclude his doing so at this time. Once the matter before him has been resolved, he intends to do so."