Marc Anthony is deep in mourning.
The GRAMMY winner broke down crying on Sunday night after paying tribute to legendary Mexican singer-songwriter Juan Gabriel -- who died at age 66 in Santa Monica, California on Sunday -- during his concert at Radio City Music Hall in New York City.
A concertgoer tells ET that Anthony was incredibly emotional and in tears after giving a speech in memory of Gabriel, recalling how the first time he saw the best-selling Latin artist perform was on the very same stage he played that night.
Anthony then asked the audience for help singing one of Gabriel's classic songs, "Abrázame Muy Fuerte."
"There was not a dry eye in the audience during this performance," the concertgoer shares.
Anthony also took to Instagram to pay his respects for Gabriel, commending his legacy and crediting the performer for inspiring his career.
Hoy el mundo de la música Latina ha perdido un gigante, un ícono y una leyenda que marcó mi vida para siempre. El es gran responsable de que mi carrera tomara este rumbo desde el primer dia. Enormemente triste con la noticia de la pérdida de uno de mis héroes. Una vida más grande que la vida misma se apaga hoy, pero tu música y tu legado quedará con nosotros para siempre. Descansa en paz mi luz. @soyjuangabriel
Gabriel's death is especially felt in his home country of Mexico, where, after news of his passing broke, mourners came together across the country, including at the statue in his honor in Mexico City, to pay their respects.