Sir Paul McCartney ''never thought'' he would be a singer-songwriter.

The 'FourFiveSeconds' hitmaker would never have dreamed of being famous and making it as a singer.

He said: ''Talk about: Pinch yourself. I never thought I would be a singer-songwriter. Who dreams of that? I think with Elvis appearing I did think, 'It'd be good to get a bit of that.' And John was thinking that, and George was. When we got together, we sort of started to dream that. It was a bit of a far-off dream, and it was just a dream. It wasn't anything that we really ever thought would turn out to be more than that.''

Despite his international fame, Paul loves doing ''normal'' things, like taking public transport or the Underground in London and thinks he is very different to the ''celebrity me'' he is in the spotlight.

The 76-year-old singer told GQ magazine: ''I quite like going on public transport. It's just my character enjoys the sort of thing that I always did. It's a roots thing. I'll sometimes go on the Underground in London, which I did the other day. I'm being me. I'm not being the celebrity me. And those moments are quite precious. Obviously I understand that if were to see Elvis or David Bowie on the Tube, I'd kind of want a photo of him, so I get it. But I've figured I have to make certain rules for myself to give me a quality of life.''