Cher at 68, 'continues to struggle with health concerns after doctors force her to cancel Dressed To Kill tour

Cher announced last month that she was canceling her remaining Dressed To Kill tour dates due to illness.

Now comes word that the 68-year-old superstar is still grappling with those health concerns and that there's no telling when she'll be able to return to the stage.

Cher is suffering from 'an acute viral infection' that affected her kidneys and her singing strength, Closer magazine is reporting.

She simply is too ill to go on performing,' a source told the publication, adding that the singer had 'no choice' but to cancel the second leg of her successful tour.

'Even with the best doctors and specialists money can buy, her health seems to have gotten worse, not better. She's putting on a brave front for her fans.'

Those elaborate song and dance routines could potentially do more damage !

Needs rest: The entertainer (pictured May 25) is said to be suffering from an acute viral infection that has affected her kidneys and her vocal strength, as Closer magazine reported