The 24-year-old brought the dog home after visiting a shelter in Louisiana, where he has been filming The Twilight Saga: Breaking Dawn.
And Rob says the dog has been keeping him company because his friends don't visit him when he films in remote locations.
The actor told Scottish newspaper the Daily Record: 'I know it's sad. A lot of actors have a bunch of people who kind of just go up and stay with them for like two months, like an entourage. But my friends, their egos are too big. They'd be like, 'I'm not part of your entourage. I'll stay in a free hotel for a bit if it's in New York or Los Angeles but I am not going to come out to some random town in the sticks.'
'But that's kind of why I adopted the puppy. It's from a shelter and he was going to be put down. I only got him two or three days ago and they only keep them for 10 days.'
Pattinson revealed that he has already been treating the canine.
He added: 'He's been freaked out. It's funny. I got a private plane here [Los Angeles] from Louisiana, where I was filming Twilight, so he came out of the shelter and the next day he's on a private plane. A bit like Lady And The Tramp.'