Gabrielle Union believes she "failed" her character in Bring It On. The actress, who played Isis in the beloved cheerleading film 21 years ago, wants to make amends for that in her new book You Got Anything Stronger?. In it, Union opens up about a letter she wrote Isis apologizing for not portraying her the way she deserved.

"I do think it was a mistake," Union explained on Monday's Good Morning America. "I was given full range to do whatever I wanted with Isis in Bring It On, and I chose respectability, and to be classy and take the high road."

Union said she did that because she thought it would make Isis "the appropriate" and "right kind of Black girl."

"Black girls aren't allowed to be angry, certainly not demonstratively angry, and I muzzled her," she continued.

Union wrote the letter while doing press last year for the 20th anniversary of the film.

"I need to come to grips and acknowledge where I failed Isis," Union added. "When given full control, I made her appropriate."

When asked what exactly she would have done differently with Isis, Union said she would've "allowed her to be angry."

"I would have allowed her her full humanity, and part of being a full human is the ability to express rage when harmed. When you don't really allow yourself your full range of emotion and you muzzle your own emotions, it allows people to think, 'Maybe what I did wasn't that bad,'" she shared. "I would have given her all the anger."

Union holds nothing back in her second book, a follow-up to 2017's We're Going to Need More Wine. That includes her very personal fertility journey. The actress and her husband, Dwyane Wade, welcomed daughter Kaavia via surrogate in 2018. In an excerpt published by Time, Union opens up about deciding to go forward with surrogacy while reflecting for the first time on Wade's infidelity nearly a decade ago.