The 46-year-old entertainer was also joined at the premiere by her co-stars in the film Will Arnett, Jenny Slate, Rosario Dawson, Zach Galifianakis, Kate Micucci, and Riki Londhorne.
Amber Rose and her three-year-old son Sebastian also attended the premiere along with Pete Wentz.
The Lego Batman Movie is set to hit theaters on Friday, February 10.
FYI: Mariah is wearing a Gucci bomber jacket. Monroe is wearing a Dolce&Gabbana dress.
10+ pictures inside of stars arriving at the premiere..