The Three 6 Mafia star, who collaborated with Cyrus on new single "23," told the audience: "I assure you she's been doing a lot more than twerking!"
Cyrus then announced: "No, I'm really pregnant!"
On Monday morning, the singer/actress responded to the pregnancy reports, posting on Twitter: "waking up to the news that I'm now pregnant with @therealjuicyj baby."
She then joked to her best friend Cheyne Thomas that she would be naming the infant "Juicy J Jr." She also tweeted: "it makes me laugh/ sad how the world is full of dumb asses."
Cyrus recently confirmed her split with fiance Liam Hemsworth and has been busy promoting her upcoming album "Bangerz."