Jay Z flies his barber to wherever he is in the world every week.

The 47-year-old rapper has had his hair cut by Johnny Castellanos, aka Johnny Cake, for the last 20 years, and though his hairdresser is based in New Jersey, the stylist makes time to see him on a regular basis, whether that's at the '99 Problems' hitmaker's New York or Los Angeles homes, or further afield.

Johnny said: ''I'm grateful every time I get on a plane. I'm really flying across the country for a haircut? Man, that's crazy.''

The barber was just 18 when he met Jay's then-manager and business partner Damon Dash, and started travelling twice a week to the rap mogul's Manhattan office for cuts.

On one occasion, he was flown out to a party in the Hamptons by Damon, where he was introduced to Jay - whose real name is Shawn Carter - and the rapper asked for a cut, joking with the young barber not to be nervous.

Johnny recalled to USA Today newspaper: ''I was like, 'Get out of here.'

''But I was nervous. I had to act like I've done this before.''

Travelling with Jay means Johnny has met the likes of the late

Michael Jackson, Quincy Jones, Stevie Wonder, Snoop Dogg and Pharrell Williams, with the 'Happy' singer now among his clients.

But Johnny never lets himself get starstruck or intimidated by the high-profile heads he shaves.

He said: ''I always had it in my mind that I need to be the coolest barber out there, and that's how I'm going to attract other customers who are high-profile.

''I'm with [Jay Z], so I can't act like a groupie or be super excited. I'm always the first to judge myself and overthink things.''

And despite his huge success, Johnny - whose clients also include Kid Rock - insists he never had a grand ''plan'' for his career.

He said: ''There was no plan. I was not doing well in school; my grandfather made a living at [barbering], I figured I could make a living at it. That's it.''