The Third Caliph, Saiyidina Uthman ibn Affan r.a.
Aisha reports: Rasullulah s.a.w. was lying down in his house with his thighs or his calves exposed. Abu Bakr asked permission to enter and was permitted while Rasullulah s.a.w. was in that position and he came in and spoke with him (s.a.w.). Then, Umar asked permission to enter. He was granted permission and came in and spoke with him (s.a.w.) while in that position. Then, Uthman asked permission and Rasullulah (s.a.w.) sat up and straightened his clothing. He was then permitted and came in and spoke with Rasullulah (s.a.w.).
After he had gone, Aisha said: Abu Bakr entered and you did not get up for him or worry about him and Umar came in and you did not get up for him nor worry about him but when Uthman came in, you straigtened out your clothing! Rasullulah (s.a.w.) then said: “Should I not be shy of a man around whom the angels are shy?”
[Sahih Muslim]