Joaquin Phoenix's dog is allergic to sunlight.

The 'Joker' star has two canine companions, Oskar and Soda, and he has to keep the latter - a white pit bull mix he rescued from being euthanised 13 years ago - inside during the day, though he has bought her a specially-made suit so he can take his pets to the beach.

However, he admitted: ''She looks so f***ing cool but she doesn't like it.''

The 44-year-old actor has been vegan since childhood and admitted he ''doesn't really like'' junk food, but still indulges occasionally.

He told the new issue of America's Vanity Fair magazine: ''I eat really healthy.

''I don't really like junk food. I don't like processed foods. Right? But I still can - like, I'll f**k up a bag of chips. Like a f***in' Subway sandwich and s**t.''

Joaquin began acting when he was a child and will never forget the ''buzz'' he felt when 'cut' was called during one of his first roles, a part in TV show 'Hill Street Blues' in 1984.

He said: ''After they said 'cut,' I remember the other people and the other actors, I could feel that they went, 'Oof.'

''There was this moment and I felt it too, like my body was f***ing buzzing. I'll never forget this feeling. It's like the first time you drink or smoke a joint or something. You're like, holy f**k, my whole body is aware of it in a way that I've never been aware. It felt incredible.

''It was an incredible feeling, and I think the organism went, 'Oh, well, huh, we're tapping something.' ''

However, the 'Walk the Line' star admitted he'd have doubts if he heard that childhood tale from anyone else.

He added: ''Does that seem believable? Really? Because if somebody told me that, I'd be like, 'You're seven years old. You really had a knowing of what the f**k you were?'(sic)''