Salaam Alaykum Sheikh,
I had read a particular supplication in a website, and it is known to be said while looking at the mirror. It reads:
“ALLAH humma anta hassanta khalqi fa Hassan khuluqi”
Can you provide me with any authentic hadith dealing with this supplication or at least let me know whether it is right or wrong?
Jazaak ALLAHu Khair.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

This Hadeeth was reported by Ibn Hibbaan in his Saheeh and by Abu Ya’ala in his Musnad on the authority of Ibn Mas’ood that the Prophet said: “O Allaah, You beautified my body, so do beautify my character.” Al-Albaani said that it is a Saheeh (sound) Hadeeth.

However, this supplication is not restricted to when looking at the mirror according to the religious texts that we have come across. Nonetheless, this was mentioned in a Hadeeth that was reported by At-Tabaraani in Al-Awsat on the authority of Anas who said: “When the Prophet used to look in the mirror, he would say: “Praise be to Allaah Who fashioned my creation and gave it a perfect form and Who shaped my face in a good form, and made me among the Muslims.” However, this Hadeeth is Dha’eef [weak].

Allaah Knows best.