CAIRO — As free speech has shriveled in Egypt, its often zealous courts have jailed democracy activists, shuttered charities and pursued gay people who waved rainbow flags at concerts.

Now the courts have a new target: a leading pop diva.

The singer, Sherine Abdel-Wahab, was referred to trial on Wednesday after a video clip of a concert circulated that showed her warning fans, obviously tongue-in-cheek, that drinking water from the Nile could make them sick.

“You are better off drinking Evian,” she said, referring to the brand of French mineral water.

Sherine, as she is known to fans across the Arab world, touched a raw nerve with Egyptian nationalists after a fan asked her to sing the tune “Have You Drunk From the Nile” during a concert.

“You’d probably get bilharzia,” she quipped, referring to a waterborne disease, also known as schistosomiasis, that is spread by parasitic worms and that the Egyptian government has struggled to eradicate.