One person detailed the not-so-nice experience with Nyong'o, reports aceshowbiz.com.
Recalling the time when the person attended an early release party for "Black Panther", the user said: "I was the 4 person to greet Lupita and tell her how much I appreciate her and how amazing she is. She didn't say anything back. After posing for a pic, she rolled her eyes."
Furthermore, the user claimed to have overheard Nyong'o complaining about her fans.
The star reportedly said that she "didn't want to be there and that she didn't care to take pictures. Rolling her eyes, sighing."
The person added: "She seemed so miserable at the event. This was the day before the nationwide release so I was like why?? woulda preferred her to not come and just relax at home."
This prompted other users to come out and say that they had experienced similar behaviour.
Someone who claimed to be an extra in "Black Panther" said that the actress "was hella rude on set".
One other person wrote: "My friend was invited to a broadway play that starred Lupita & the actress who invited my friend. My friend went back stage and everyone left from the same back door. Lupita was apparently very rude to the fans who were back there waiting on the cast."
Meanwhile, another tried "not to think anything of it" when Nyong'o was being rude to her.
"I figured it could've just been an off night. She posed for pictures with some, but seemed like she wanted to be anywhere but there."
The actress has yet to respond to this.
( With inputs from IANS )