James Corden has gotten plenty of A-list guests to star in his "Carpool Karaoke" segment with him, but only one experience trumps them all.
ET spoke with The Late Late Show host on Monday night at the Carpool Karaoke: The Series Party at the Chateau Marmont in Los Angeles, where he talked about the stunning success of the segment, which now has its own Apple Music spinoff series. Corden said that while he couldn't pick a favorite installment, he did have the best time with Bruno Mars.
"I mean, it's a bit like picking your children, you know what I mean?" he joked to ET's Kevin Frazier. "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."
WATCH: EXCLUSIVE: James Corden on Landing Mariah Carey and Bruno Mars for 'Carpool Karaoke,' Plus, Is Brad Pitt Next?
As for his favorite guest on his new series, Corden teases a few incredible episodes. Aside from Corden's appearances, hosting duties on the 16-episode series will actually also be split between different celebrities. New episodes stream Tuesdays on Apple Music.
"I've done the first one with Will Smith, which is just a dream for me," he said. "And the last episode is me and LeBron James, which is a really amazing episode. It starts in an empty Staples Center and ends with a huge, huge ending to the series."
"But in terms of the ones that I really love, I really enjoyed the whole Cyrus family," he continued. "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."
Corden, 38, also talked about expecting his third child with his wife, Julia, who's due in December. The couple is already parents to their 6-year-old son, Max, and their 2-year-old daughter, Carey.
"He's doing good," Corden replied when asked about the baby.
"I thought we were out at two and then actually, you know, you forget about that first year pretty quick and then I don't know," he added about becoming a family of five. "I'm trying to explain it because lots of my buddies are going, 'Dude, are you mad? What are you doing?' And I sort of go, well, the two that we've met, you wouldn't think this but I think they're the best people on the planet. So, I'm like, they're the best people I've ever met, so I want to meet another one, you know? I'm excited."
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As for his show's recent Emmy nomination for Outstanding Variety Talk Series, Corden says he's actually not competitive with the competition.
"Genuinely, if anything, the opposite," he said. "Everybody sends each other gifts. We had ice cream sent to us from the Stephen Colbert show and we sent everybody popsicles. Look, I'm thrilled to be nominated again. It's so lovely and so terrific for our show. Like, we're a small show. We have a small team, but I feel like we try and punch up above our weight as best as we can."
Watch the video below to see Ed Sheeran 's "Carpool Karaoke" segment from June, which had the "Shape of You" singer dishing about wild nights out with Justin Bieber.