Amanda Seyfried's dog helped her ''find her independence''.

The 33-year-old actress adopted her Australian Shepherd named Finn after they met on the set of HBO show 'Big Love', which ran from 2006 to 2011, and has said having the pooch around has ''completely changed [her] life'' for the better.

She said: ''As soon as he was mine, like 24 hours after I got him, I realised something about me needed him. He completely changed my life and helped me find my solitude and my independence. When you have a lifestyle like I did when I was in my early twenties, there were no constants.

''It was just hard to know where I was going to be the next month because of my career. That's why I got him.''

The 'Mamma Mia!' actress also credits Finn with being her ''anti-depressant'', and says she now can't go anywhere without her furry friend.

She added: ''My anti-depressant has been a lifesaver. I just can't picture being anywhere without him. Except England. Every time I do a movie over there, I have to leave him. I wouldn't put him through that plane ride unless I was there for long enough to make sense because he has such a good life when he's being babysat by my agent.''

And although Amanda loves rescuing animals - including a white donkey named Gus - she won't be getting another dog any time soon.

Speaking to People magazine, she said: ''I can only have one dog. Everybody's like, 'Are you going to rescue another dog?' I'm like, 'Finn's an individual, and he is very particular and I know what he needs and I know what he wants' As much as I love dogs and love rescuing animals, all the animals I rescue are not dogs. I can still be in the rescue game, but he's an elder now.''