While many were happy to hear Birds of Prey (And the Fantabulous Emancipation of One Harley Quinn) would be rated R, Warner Bros. wasn't so sure about it at first.

Speaking with VarietyMargot Robbie said, "it took a bit of convincing." It was mentioned that pitching the idea of an R-rating was especially difficult because 2016's Deadpool hadn't yet been released.

RELATED: Birds of Prey Funko Pops! Reveal New Harley Quinn, Black Mask Looks

Since the release of Deadpool, R-rated comic book films have seen great success, such as 2017's Logan and 2018's Deadpool 2. What's more, Todd Phillips' Joker recently surpassed Deadpool and Deadpool 2 as the highest-grossing R-rated film. Meanwhile, a third Deadpool is said to be in the works at Marvel Studios, though the official rating hasn't been announced.

On the DC front, James Gunn's The Suicide Squad is also said to be R-rated and will similarly feature Margot Robbie as Harley Quinn. The film is set to release on Aug. 6, 2021.

RELATED: Fight Club Helped Influence Harley Quinn and Birds of Prey's Costumes

Directed by Cathy Yan from a script by Christina Hodson, Birds of Prey (And the Fantabulous Emancipation of One Harley Quinn) stars Margot Robbie, Jurnee Smollett-Bell, Mary Elizabeth Winstead, Rosie Perez, Ewan McGregor, Steven Williams, Derek Wilson, Dana Lee, Francois Chau, Charlene Amoia, Chris Messina and Matthew Willig. The film arrives Feb. 7.