In 1999, it was reported that Haddad had officially embraced Islam in honour of her deceased Muslim mother Mouna who died in 1998. She went on to do Umrah that same year in Mecca. It was also reported that her decision was met with strong opposition from her Maronite Christian father and some of her relatives. Eventually, her father respected her decision. She is the only one of her siblings who practices Islam. Haddad rarely speaks openly about her religious beliefs stating that these matters "are personal and only between her and God." Prior to her official conversion, Haddad did thorough research into Islam. She once stated in an interview with Al-Jareema magazine that attending the lectures of Islamic scholars Sheikh Al-Shrawi and Tarek Swaed is also what motivated her to convert. Haddad describes herself as a "private, yet observant Muslim" who prays, reads the Qur'an and fasts during Ramadan. She denied rumours that she embraced Sufism or returned to Christianity after her divorce. Haddad's father died in late 2011, thirteen years after the death of his wife Mouna. The track "Rajaa Al Sheti" on the 2011 album "Bent Osol" was devoted to Haddad's parents.