Sir Paul McCartney is influenced by Beyonce.

The 71-year-old singer/songwriter makes a point of checking out the live shows by current chart artists because he wants to make sure his own concerts don't seem ''old fashioned''.

He said: ''If I'm gonna do a tour I like to go and see what other people are doing. I don't wanna bring my tour out and be amazingly old-fashioned.

''So if people are going, 'Oh man Beyonce, she was killer!' I like to go there and go, 'Yeah, we can do better than this.' ''

Last year, Paul saw Jay-Z and Kanye West's 'Watch the Throne' gig at The O2 in London and he says the show made him appreciate the ''poetry'' of hip-hop.

He explained to NME magazine: ''I was expecting it to be, 'Oh it's great, it's hip-hop, it's loud,' but I hadn't until then got the urban poetry element.

''Like, Bob Dylan is a poet. And so is Jay Z and so is Kanye.''

The Beatles legend admits he doesn't understand the key to his own success.

He said: ''People used to say to The Beatles in America, 'Who writes the words and who writes the music?' And we'd say, 'Both of us.' 'So what's your formula?' We'd go, 'Well if we had one, we'd bottle it but then probably break the bottle and lose the formula.' You know, you don't want a formula. I don't ever want to find out what I'm doing.''