Monroe has beaten the likes of Lucy Boynton, Merritt Patterson, Brittany Robertson, and Gabriella Wilde for the part, reported Aceshowbiz.
The replacement has met with flak from fans, who took to Twitter to express their disappointment. "Why did you recast Mae Whitman? Like really?" said one.
Among the angry fans was Anna Kendrick who also didn't agree with the replacement. She tweeted, "@maebirdwing is talented as hell, and just proved she can carry a film."
Dean Devlin, Emmerich and Harald Kloser produce the movie while James A Woods and Nicolas Wright wrote the most recent draft. The sequel currently titled "ID Forever Part 1" will hit U.S. Theatres on June 24, 2016.