Kelly Rowland's decision to join Chris Brown on his US tour has allegedly "seriously worried" her bosses on 'The X Factor'.

Last week it was announced that the 'Motivation' singer will be joining Brown for three weeks of his 28-date tour, which starts on September 12 and heads to cities in Canada and the US but now her show bosses are concerned about the timing.

If Rowland is supporting the 'Look At Me Now' singer, it means that she will be in the UK just a few days before the live stages of 'The X Factor' is due to start.

A show source said: "Kelly is taking a real risk jetting off in the middle of her first series of The X Factor. Some of the cast and crew are worried she is not taking it seriously."

Rowland insists that she's dedicated to the UK's 'X Factor' and now a spokesperson has denied that she won't be able to meet with the hopefuls that she will be mentoring.

A representive has said: "She plans to have regular Skype chats and phone calls while she's on tour."

Do you think Kelly Rowland will be a good judge on the show?

Kelly Rowland has a nip-slip on Stage!