AceShowbiz - Jennifer Garner got back into action mode for her new movie Peppermint by taking up mixed martial arts.

The Dallas Buyers Club star plays a woman seeking revenge after her husband and daughter are killed in a drive-by shooting right in front of her and she explains her physical training helped her connect to the character.

"I've been training for a while on this," she tells People magazine. "I did (mixed martial arts) MMA skills, gun skills, knife skills. It was the connection to the physical that made me kind of understand her fight for her daughter."

"She (Garner) was very physical, she was very fit - even before we started training," director Pierre Morel adds. "She was dead-on, ready to go for it. The fact that everything is done by the actor is key."

Jennifer, who has starred in action-packed roles in Alias and Daredevil, was "excited" to take on Peppermint after reading the script because it was "an original story and there's a strong woman at the middle". She was hooked by the way her character reacted to losing her family.

"She just shuts down her heart, goes into hiding and spends the next five years becoming a machine," she says. "She immediately takes matters into her own hands to make sure those people are brought to justice.

"The fact that she just says, 'I'm a mom, I'm taking care of this and I'm going to do what I need to do'... that, I'm inspired by. I've never gotten the chance to play that kind of visceral need to defend, or protect, or take care of someone in your family."