Singing and acting by women as seen in the modern world media is prohibited in Sharia. The Prophet (peace be upon him) says: “from among my followers, there will be some people who will consider illegal sexual intercourse, the wearing of silk, the drinking of alcoholic drinks, and the use of musical instruments, as lawful.” Reported by Bukhari. He compared four things that are among the major sins.
If the lyrics of the song are chaste words, and not sinful words, nor what goes against the Shariah, and she sang in the midst of other women in a wedding, or sang among her Mahram and husband; all these are permissible in Shariah.