Bulugh al-Maram #1275

Narrated Anas (RA): The Prophet (ﷺ) said: "Observe her, and if she gives birth to a child which is white complexioned with dark hair, her husband would be its father. But if she gives birth to a child with eyes looking as if they have antimony (Kuhl) in them and curled hair, the man whom her husband charged her with committing adultery is its father." .