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Jennifer Aniston and Justin Theroux have a "new member" in their family.

"We have a little puppy, Sophie, a rescue," Aniston, 43, said on The Tonight Show With Jay Leno Friday. "A little pit boxer."

Aniston and Theroux, 40, decided to adopt after Aniston's "extreme animal activist" pal called her up and said 10 puppies were "left in a box in front of a shelter."

"Sophie came up to us, and that was sort of a big indicator of they choose you," the Wanderlust actress said. "We were there for three hours, and I'm telling you, I was almost walking out with three puppies. It's so hard. That's why we named her Sophie, because it was Sophie's Choice. I was crying -- it was so hard."

Aniston added that she and Theroux are currently crate training Sophie, "but she doesn't love" being "trapped in a cage."

"I have a white German Shepherd, Dolly, and she loves her crate. We were a little nervous about them getting along," Aniston admitted. "Dolly doesn't have a create anymore but she loved it. Somehow she walked her way into Sophie's crate, which is tiny. . . It was good because Sophie was like, 'I love going wherever you go.' They slept there together the whole night."