Jennifer Aniston named her puppy after 'Sophie's Choice'.

The 43-year-old former 'Friends' actress admits she had such a hard time choosing which homeless puppy to adopt that it reminded her of the 1980 book in which a Polish mother is forced to pick which of her two children gets sent to the gas chamber at a Nazi concentration camp.

She said: ''We were [at the shelter] for three hours. I was almost walking out with three puppies. That's why we named her Sophie, because it was [like] 'Sophie's Choice'. I was crying - it was so hard.''

She and boyfriend Justin Theroux sped to the shelter after a friend tipped them off to the arrival of a litter of 10 puppies - from which she eventually picked pit bull mix Sophie.

She told 'The Tonight Show with Jay Leno': ''They were left in a box in front of a shelter - so heartbreaking. So we ran over.

''Sophie came right up to us. That was sort of a big indicator - they choose you.''

In between bonding with her new pet and shooting movies, the 'Wanderlust' star reveals she still likes to watch episodes of ''Friends' that she stumbles across on the television.

She told 'CBS This Morning': ''I get very nostalgic and I sort of sick back with pride and ... it makes me happy. I've forgotten complete episodes that we shot, so there's times I watch it just as if I'm watching for the first time.''