James Corden felt "depressed" after his 'Carpool Karaoke' with Bruno Mars, because he was sad it was over.

James Corden

James Corden

The 'Late Late Show' host has admitted his favourite guest in his popular musical car journey segment was the '24K Magic' hitmaker, as he was left feeling emotional at the end of their time together because he had been "looking forward" to meeting the star for "so long".

Asked who his favourite guest has been, James, 38, said: "I mean, it's a bit like picking your children, you know what I mean? But in terms of the one I've enjoyed doing the most, I think it was probably Bruno. Like, I really, I got a bit depressed afterwards ... Because I'd been looking forward to it for so long and I'm such a fan. When we were done, I was like, 'Oh. I'm not gonna get to do that again,' you know, and so that was incredible."

The hugely popular segment is set to get it's own 16-episode series on Apple Music entitled 'Carpool Karaoke: The Series', and James "really enjoyed" getting to drive around with brand new guests, including Miley Cyrus and her family.

He added to 'Entertainment Tonight': "In terms of the ones that I really love, I really enjoyed the whole Cyrus family. So, it's Miley, Noah, Billy Ray - everybody - all of them in a huge car. It's really quite amazing. You really feel like you're watching that family on a road trip, you know? And then Billy [singing] Metallica is hilarious. There's so many. I'm so proud of it."

One guest James won't be having on his show any time soon is former Oasis frontman Liam Gallagher, as the 44-year-old musician recently slammed the television host as a "k**b head".

Asked if he'd ever appear in the segment, Liam said: "No, thank you very much. No f***ing chance mate. With that fat bloke from 'Kevin and Perry'?"

To which his girlfriend and manager Debbie replied: "It's called 'Gavin and Stacey' and you've never watched it."

Liam insisted: "I don't need to watch it to know I won't like it. James Corden is a k**b head."