Q. Is it permissible for the woman to wear the white wedding dress knowing that it is imitation of the Jews and the Christians. Some of the women have said if the intention in doing so is not for the purpose of imitation, rather for the purpose of beautification for the husband then it is permissible. Is this correct?
A. If it is known that it is a dress specifically for the Jews and the Christians and that it is imitation, then the Hadeeth is general,
"Whoever imitates a people, then he is from them"
(Musnad Ahmad, Declared good by Al-Albaani)
It is not a condition that the person has the intention to imitate or not (it is still imitation).
Source: Fataawa Al-Mar'ah Al-Muslimah lil-Imaam Al-Waadi'ee pg. 282 question #307.
Sisters Upon Al-Istiqaamah