Entertainment Tonight ET Online ETOnline.com

Milla Jovovich doesn't take too kindly to unfair criticism as we found out in a recent interview where the actress revealed her secret feud with a finicky tweeter.

Milla started filming the fourth installment of her butt-kicking Resident Evil franchise shortly after giving birth to her daughter, Ever. The actress admitted that her body, while still impressive, wasn't the same as it had been for the previous films, but that didn't give strangers the right to critique her.

"One dude wrote, 'God, your arms aren't as toned in the poster as they were in the other movies,'" said Milla, who used the comment as motivation to get in tip-top shape for the upcoming fifth installment. "I was like, 'Alright, dude, you think my arms were flabby on the last poster, look at this one!'"

Milla threw herself into training about 8 months prior to shooting Resident Evil: Retribution. Her commitment may seem extreme to some, but to those who work with her, it falls right in line with her work ethic.

Co-star Boris Kodjoe sustained several injuries during filming, including a hyper-extended knee and bruised ribs, just to keep up with Milla.

RELATED: Actors Injured On the Set of Resident Evil 5

"I jumped in there because I can't punk out," said Boris, who -- like Milla -- performed most of his own stunts. "If Milla does everything, what am I going to say, 'No, I can't do that, please?'"

Watch the video for more. Resident Evil: Retribution opens September 14.