From Sahih Muslim (Hadith 7198):
A'isha reported that she heard Allah's Messenger (ﷺ) as saying:The people would be assembled on the Day of Resurrection barefooted, naked and uncircumcised. I said: Allah's Messenger, will the male and the female be together on the Day and would they be looking at one another? Upon this Allah's Messenger (ﷺ) said: 'A'isha, the matter would be too serious for them to look to one another
Reference: Muslim 7198