Hassidic music stars Avraham Fried and Yaakov Shwekey are to perform in Jerusalem before an audience of over 10,000 Thursday night - but leading hareidi-religious Rabbis Yosef Shalom Elyashiv, the Gerrer Rebbe and others say it's forbidden to participate or attend events of that nature. Flashy posters all over Jerusalem and elsewhere advertise a high-powered Hassidic music concert scheduled for Thursday evening at Teddy Stadium. It features two of the genre's greatest stars, Fried and Shwekey, as well as guest appearances by Aharon Razel and the up-and-coming Elad Shaar. Called "L'Chaim in Jerusalem," the event commemorates the 40th anniversary of the reunification of Jerusalem, and will feature an extra-large orchestra. A damper was placed on the event, however, in the form of a rabbinic ban appearing in the hareidi-religious press. The ban is signed by leading rabbis including Rabbi Yosef Shalom Elyashiv, the Gerrer and Bezler Rabbis, Rabbi Aharon Leib Shteinman, Rabbi Shmuel HaLevy Vozner, Rabbi Chaim Pinchas Sheinberg, and more. . The Rabbincal statement reads: "We trembled at hearing about the terrible breach in our camp of 'music evenings' and 'concerts' in which musicians sing before men and women sitting together, Heaven forefend, and even not together. All Torah leaders have in the past clearly forbidden these events, even when men and women are separate." The rabbis say the ban applies to men, women and children and of course the performers. Newspapers are not permitted to advertise these events, according to the ad, and musicians who sing "in front of men and women together" must not be invited to sing at other events. A source close to one of the above rabbis told Arutz-7 he was unsure of the grounds for the ban. He opined that it could be because of the mixing of the genders outside the event, but added, "This is very puzzling, because why then is there a difference between performers - who are penalized only if they sing before a mixed crowd - and the general public, which is forbidden to attend under all circumstances?" Another source said that it was possibly the rock-and-roll atmosphere prevalent at events of this nature that might be the problem, though this was not mentioned in the ban. One source said he believes one of the rabbis signed this ban several years ago, and that it was not presented to him again. Others expressed a lack of confidence in the entire system of "signed rabbinic decisions," in that it is not clear how the situation was presented to the rabbis. There have even been cases of rabbis who said their names were "signed" on various announcements without their permission. "It is known that Rabbi Moshe Feinstein [the pre-eminent Torah authority in the U.S. in the 20th century - ed.] permitted events of this nature if the proceeds were for charity," a source close to one of the rabbis said, "as is the case in Thursday's concert, so I'm not sure how to understand this." Producer Moshe Ben-Zimra told the NRG website in response: "Men and women will be totally separated at the event, including separate entrances, and everything is taking place under the supervision of great rabbis. I greatly respect the rabbis who signed the ban, but they were misled by their underlings whose purpose is simply to liquidate Hassidic music in Israel. The rabbis don't realize that this event is kosher and maintains the laws of modesty. Over 10,000 people have already bought tickets, and they can rely upon the Torah rabbis who support separate and modest events of this nature."