'Megan Leavey' star Kate Mara says she and sister Rooney Mara bond over both being actresses

"When she became an actor, we actually lived together in my apartment," she said

— -- Even though she always knew she wanted to be an actress, Kate Mara was quite the introverted child, she says.

Now, in what might be the performance of her career, Mara takes on the titular role in the film “Megan Leavey,” which follows the true story of a Marine’s relationship with her bomb-sniffing dog, Rex.

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“So from the time I was 14 ‘til, I think, my sister started acting when I was 20, 21, I didn’t have someone to share this craziness with,” Kate Mara said. “So when she became an actor, we actually lived together in my apartment for the first year or two.”

The sisters have also bonded over their auditions and when their movies didn’t exactly have positive reviews, Kate Mara said.

“We would both go on auditions and come home and talk about the terror of certain auditions and funny stories and so it just became something super special that you can actually bond with a sibling with which is very rare,” said Kate Mara.

Lately, Kate Mara, who will next take on the role of teacher and campaign aide Mary Jo Kopechne, has been busy planning her wedding to actor Jamie Bell. Mara said her two Boston terrier dogs will be in her wedding.

“He’s great with them,” Kate Mara said of her dogs’ relationship with her fiancé.

“If he wasn’t, we wouldn’t be getting married.”

Watch the full interview with "Megan Leavey" star Kate Mara ABOVE.