Maliks Muwatta Book 20, Hadith Number 13.

Section : Wearing Clothes when in Ihram.

Yahya related to me from Malik from Yahya ibn Sa’id that he heard Said ibn al Musayyab say, about the girdle worn by some one in ihram under his clothes, “There is no harm in it if he ties the ends together as a belt.”

Malik said, “This is what I like most out of what I have heard about the matter.”