When you're trying to help someone who has a serious illness, they have to help themselves first

Brian Littrell, band member

McLean, 23, will be in a rehab centre for some 30 days, to be treated for clinical depression, anxiety and alcoholism.

The statement on the band's website says: ""AJ is our friend and our brother and we whole-heartedly support him during this difficult time. Fortunately, AJ has realized he can't solve his problems by himself."

Troubled

The other members of the band recently appeared on MTV Total Request to discuss their troubled colleague.

All four were very emotional, as were the teenage fans in the studio audience.

"When you're trying to help someone who has a serious illness, they have to help themselves first before they can really receive help. They've gotta really want it," said Brian Littrell, 26.

AJ McLean: Being treated for alcoholism and depression

The band believe McLean's recent problems are due in part to the recent death of his grandmother.

Kevin Richardson said: "He's been burning the candle at both ends and partying quite a bit to escape it. His alcoholism is - it's pretty bad. And we're worried about him."

The group's tour was originally planned to conclude in Vancouver on 7 August. The new itinerary has the tour resuming on that date and ending on 28 September in Alberta.

The 19 cancelled dates will be performed in September instead, and fans can exchange or refund their tickets as necessary.

Nick Carter insisted that the group will stay together despite McLean's illness. "I don't think there is an end to this group until one of us dies," he said.

Their latest album Black and Blue has sold 8 million copies since its November release.