Hadith -- Bakr Eid

Narrated Ibn Abbas (Radi-Allahu 'anhu):

The Prophet (Sallallahu 'Alaihi Wa Sallam) was asked about a person who had
his head shaved before slaughtering (his Hadi) (or other similar ceremonies
of Hajj). He replied, "There is no harm, there is no harm."

Bukhari Vol. 2 : No. 779