The "Black Panther" star uploaded a video to Twitter on Wednesday showing her hitting the convention floor undercover as one of the Mighty Morphin Power Rangers.
In the nearly minute-and-a-half clip, set to Kendrick Lamar's "i," Nyong'o is seen dancing like a fool around the San Diego Convention Center, posing with toys based her "Star Wars" character and snapping selfies with unsuspecting cosplayers.
At one point, she even cheered with fans as the cast of "Thor: Ragnarok" did an autograph signing.
An un-costumed Lupita later joined co-stars Chadwick Boseman, Danai Gurira, Michael B. Jordan, Daniel Kuluuya, Letitia Wrigt, Forest Whitaker, Andy Serkis, Winston Duke and director Ryan Coogler inside Hall H for Marvel's big presentation.
Get the lowdown on the "Black Panther" footage screened for the crowd and more updates on the MCU below: