Reformed British pop stars 5Ive have warned One Direction to stay grounded or face the prospect of burning out early.

The five-piece - Scott Robinson, Ritchie Neville, Abz Love, Sean Conlon and J Brown - found fame as a boyband in the 1990s but struggled to cope with life in the spotlight and crumbled under the pressure before disbanding in 2001.

They have since reunited, without Brown, for hit U.K. reality Tv series The Big Reunion and a number of gigs around Britain, and Conlon, who joined 5ive at the tender age of 16 and suffered a breakdown shortly before the split, has some sage advice for the What Makes You Beautiful hitmakers.

He tells Britain's Daily Star, "They are just kids at the end of the day. It would be easy for them to lose their marbles (go crazy). It totally messes with your head... 1D (One Direction) must have so many people dictating what they should say and do. They should express themselves now or they will really regret it."

Robinson adds, "There will be people blowing smoke up their a**e all day long telling them they are amazing. If you believe your own hype you will turn into a monster... I would say to remember who you are, who your mates were before. The hangers-on don't matter."