James Corden thinks doing 'Carpool Karaoke' with Sir Elton John was worth "hundreds of thousands of dollars".

James Corden

James Corden

The 37-year-old presenter welcomes the 'Rocket Man' legend into his vehicle as the next guest on his popular 'Late, Late Show' segment and knows he is very "lucky" to be treated to such a personal performance.

Asked what viewers can expect from Elton, whose appearance airs during the show's Super Bowl special, James said "We did 'Crocodile Rock,' and it's flamboyant.

"To sing 'Tiny Dancer' with Elton John in a car, you just think: If this was an auction prize, it would go for hundreds of thousands of dollars. I feel lucky every time I get in the car with any of these people who I just really admire and respect."

And James thinks his carpool guests - who have included Justin Bieber, Mariah Carey, Adele, One Direction and Coldplay's Chris Martin - have an equally nice time belting out their back catalogues.

Discussing Chris' recent appearance, he told Entertainment Weekly magazine:

"After every song he was like, 'Oh, I haven't heard that for ages!' Or, 'It brings me back to where I wrote this!.

"It's actually quite a lovely thing for them to reminisce; they hear their whole career in eight songs."

The British star thinks the segment shows a very different side to his guests.

He said: "There's an ease and an intimacy to it where you'd never ever see stars quite so unguarded.

"l'm different from when I'm doing the show when there's an audience of 200. Seeing a huge megastar sing their hits in the same environment that you and I sing on our way to work -- it's humanising."

This came after it was revealed by eBay UK that a car stereo has been sold every minute on site in the last three months - perhaps in part to do with the huge popularity of James' Carpool Karaoke.

The site says that the segments could have an effect on the British public, with listings on site for 'car stereo' currently reaching over 60,000.

Perhaps also linked in is the fact that more than 80 karaoke machines have sold every day in the past three months, with the most expensive priced at £1,800 and a portable system selling for just £20.