Former Pussycat Doll star Kimberly Wyatt thinks One Direction's huge success is down to great timing and "crazy" fans.

The British boy band - comprising Harry Styles, Niall Horan, Zayn Malik, Liam Payne and Louis Tomlinson - have risen to international stardom thanks to their catchy tunes and cheeky charm.

Wyatt has revealed what she thinks the heartthrobs' secret to success is.

Talking to British newspaper The Sun, she explained: "Girls make for pretty crazy fans. They go mad for their boy bands. Timing’s been a big part of their success, so is the look of them and they hit the market at the right time — and had the right songs."

Wyatt also dished out some advice to the five-piece adding: "Don’t let your ego get the best of you. Know that the person next to you is always your lifeline to longevity and don’t forget you’re not bigger than your group."

The Pussycat Dolls disbanded in 2009 after announcing a brief hiatus, with Nicole Scherzinger's reportedly diva-ish attitude blamed by some for the break-up of the group.

However, Wyatt insists this wasn't the case.

Wyatt explained: "I think Nicole wanted a solo career and that’s just it — end of. But when we ended up being a part of the group I was a huge advocate of hers. I even helped teach her how to dance and stayed after rehearsals to make her feel comfortable within her own skin and dance movement.

She added: "I think ultimately Nicole deserves happiness. The Pussycat Dolls for many of us was our ambition but I don’t think Nicole always had that. She always wanted to be a solo artist, there’s no harm in that."