One Direction star Liam Payne has revealed that he worries about Zayn Malik and the effects of fame on him.

The five lads have had their worlds turned upside down since taking part in the X Factor in 2010, with global success later following.

Talking to The Sun, Payne admitted that he feels his bandmate Malik hasn't quite got to grips yet with fame and all the attention yet. He said:

"The only person I really worry about is Zayn, because I don't think he's quite accustomed to all of this. He's had a terrible time on Twitter, as did Danielle [Peazer, former girlfriend]."

He continued: "I don't think he’s quite adjusted to it yet, I'm sure he'll get it. He's my best mate. I've got to look out for him. It's mad to think I didn't know them two years ago and now they're my best mates."

As previously reported, Malik recently admitted in an interview that he had been called a "terrorist" on social networking website Twitter.