Janet Jackson has cancelled the first leg of her Unbreakable tour. Jackson broke the news on Twitter that she is going into hospital for an operation, but the Twitter message gave no details of the surgery involved.

"Please pray for me, my family and our entire company during this difficult time,” she said.

According to official sources, there will be no further comment on her health.

Jackson is scheduled to play Dublin’s 3Arena on April 2, 2016. The hope is that this might be far enough away to enable the singer to fulfill the commitment – but clearly that is now far from certain.

Jackson’s return with Unbreakable in 2015 was remarkable. The album went to No.1 in the US Billboard Charts, delivering her seventh No.1 album in the United States. It also topped the charts in Canada, but was not as big a hit on this side of the Atlantic, peaking at No.11 in the UK.

In a spectacular career, to date Jackson – who is sister to the late 'King of Pop', Michael Jackson – has sold approximately 160 million albums. She is just outside the all-time top 10 best selling female artists in the US.