Genesis 38:13

Then said Judah to Tamar his daughter in law, Remain a widow at thy father's house, till Shelah my son be grown: for he said, Lest peradventure he die also, as his brethren [did]. And Tamar went and dwelt in her father's house.

And in process of time the daughter of Shuah Judah's wife died; and Judah was comforted, and went up unto his sheepshearers to Timnath, he and his friend Hirah the Adullamite.

And she put her widow's garments off from her, and covered her with a vail, and wrapped herself, and sat in an open place, which [is] by the way to Timnath; for she saw that Shelah was grown, and she was not given unto him to wife.

When Judah saw her, he thought her [to be] an harlot; because she had covered her face.