Sahih Muslim Book 31, Hadith Number 6011.

Chapter : The merits of Umm Sulaim, the mother of Anas b. Malik and Bilal (Allah be pleased with both of them).

Anas reported that Allah’s Apostle (may peace be upon him) said: I entered Paradise and heard the noise of steps. I said: Who is it? They said: She is Ghumaisa, daughter of Milhan, the mother of Anas b. Malik.