Sahih Muslim Book 7, Hadith Number 2795.

Chapter : Types of Ihram- It is permissible to enter into the state of Ihram singularly for the sake of Hajj or for tamattu’ bi’l-‘umra ila’l-Hajj or for both hajj and ‘umra together.

Jabir b. Abdullah reported that the Apostle of Allah (may peace be upon him) ordered us to put on Ihram (again) as we proceeded towards Mina after we had put it off (i.e. on the 8th of Dhu’l-Hijja). So we pronounced Talbiya at al-Abtah.