From Sahih Bukhari (Hadith 6771):
Narrated `Aisha:Once Allah's Messenger (ﷺ) entered upon me and he was in a very happy mood and said, "O `Aisha: Don't you know that Mujazziz Al-Mudliji entered and saw Usama and Zaid with a velvet covering on them and their heads were covered while their feet were uncovered. He said, 'These feet belong to each other
Reference: Bukhari 6771