James Corden's Carpool Karaoke owes much of its success to a chance meeting on the set of Teachers

But when it comes to his TV career, which is now blossoming so rapidly and at such a scale that he has become a global star in little more than 12 months, I think a lot of the credit should go to Ben Winston.

Outside of the TV industry, he is not a household name, except in homes that feature One Direction fans who know him as the director of their videos.

But in actual fact, behind the camera Ben plays a huge part in Corden’s The Late Late show success.

And having now watched them working together in the flesh in America, I can say that Ben is very much James’s eyes and ears during the filming process, someone who is often by his side even during the ad breaks.

The pair also work very closely and brainstorm ideas together, including sketches like Drop the Mic and of course the global phenomenon that is Carpool Karaoke.

But the dynamic duo would never have got together had it not been for a chance meeting on the set of Channel 4 comedy-drama teachers two decades ago.

Ben explained to me: “Myself and James met on the set of Teachers. I was 18, I was just a runner and James had a small part in the drama, he played a character called Jeremy with just a few scenes. We immediately got on very well.

“We were filming up in Bristol and everyone stayed in Bristol so we spent a lot of time together.

“Even though we both had small roles in that TV series we both recognised huge ambition in each other and we felt like we had got on straight away.

“We were very good friends and we spoke all the time but we didn’t start working together until 2009 when we did the Smithy Sketch for Comic Relief, when he meets the England team, and that was the first thing I directed him in. We came up with it together.

“We did another one in 2010 and again in 2011 when, during the sketch, we had George Michael singing in a car with Smithy and that was, I guess, where Carpool Karaoke was born.”

At the time it was just two friends giving up some of their time for a charity sketch. But as everyone can see, things have developed from there.

They worked together more and more, including a 2014 documentary called when Corden Met Barlow.

It was a BBC1 doc with Ben Winston again behind the camera, and as in the years before, Corden belted out hits with an A-list singer.

In the same year, when he was thinking of trying to take a sitcom to America, Corden flew out to Los Angeles with his friend Ben.

But instead he was offered a job hosting a chat show by CBS.

Fast forward to March 2015 and The Late Late Show with James Corden began, with one Ben Winston as executive producer.

Before going on air, Ben and James discussed many points of the chat show. Ben had an unusual vision for the layout of the studio, where the audience are almost on the stage and there are areas to film everywhere, as part of a 360-degree design.

The pair also decided they would create Carpool Karaoke. Once Mariah Carey agreed to take part – dozens of others had said no – a phenomenon was born.

And Ben’s company Fulwell 73 will now make Carpool Karaoke as a spin off show, netting the friend even more money and success.

So, it turns out that Channel 4 comedy-drama Teachers wasn’t just a stepping stone for Andrew Lincoln to move onto greater things…

Mark Jefferies is Showbiz Editor at the Mirror and co-edits their Square Eyes TV Column. He flew to Los Angeles with Virgin Atlantic