It wasnarrated that 'Ali said:
"The Prophet (ﷺ) said to me: 'Donotshow your thigh, and do not look at the thigh of anyone, living ordead.'" (PT)
English reference (PT): Vol. 1, Book 6, Hadith 1460 (PT)
Arabic reference (PT): Book 6, Hadith 1527 (PT)