Christina Aguilera's Carpool Karaoke Included An Unexpected Cameo & So. Much. Nostalgia.

Christina Aguilera just made millennials' karaoke fantasies come true. Hopping in James Corden's famous Range Rover, the "Lady Marmalade" singer crooned her instantly iconic hits for The Late Late Show audiences just like it was 2002 all over again. And Aguilera’s Carpool Karaoke included a Melissa McCarthy cameo — which may initially come as a surprise, until you remember that the two appear together in Life of the Party, a college campus comedy that premieres in May.

Corden and Aguilera took a thorough dive into the 37-year-old Burlesque star's most unforgettable songs, fearlessly belting out generation-defining anthems like "Beautiful," "Fighter," and, of course, "Genie In A Bottle." Speaking of making fans' wishes come true, you won't want to miss the moment when McCarthy suddenly appeared in the backseat, leaping up to deliver Redman's powerhouse rap from "Dirrty." "I have been here the entire time," McCarthy deadpanned.

The best part? Corden enlisted Aguilera for a quick brush-up on those diva basics, handing everyone a pink rhinestone-encrusted mic and asking her how to show off his pipes like an early millennium pop goddess. "I feel like in our heads Melissa and I, we think we could be divas, but we need someone to teach us the true technique," he quipped, as Aguilera demonstrated exactly how it's done.

Of course, Corden wasn't exactly there just to sing. Probing Aguilera about the dynamics between her famous '90s Mickey Mouse Club co-stars, he couldn't resist throwing in a few questions dwelling on the teen romance sagas of fellow alums Justin Timberlake, Britney Spears, and Ryan Gosling. "Even then at that age, could you find yourself getting lost in Ryan Gosling's eyes?" he teased.

"I think there were crushes, but I wasn't on the train," Aguilera answered, diplomatically. "There was like a me and Britney [thing], there was like a thing back then. It was a good time." She confessed that even two decades ago, though, Timberlake undoubtedly "had swag," and served up some deliciously candid real talk about young Gosling, confirming, "He did have a crush on Britney." Wow. Add that one to the top of the Mouseketeers Missed Connections list.

Since wrapping her time as a judge on NBC's smash-hit singing competition The Voice in 2016, Aguilera has certainly been keeping busy. Besides crooning original singles for Netflix's The Get Down or serving as an executive producer on Spike TV's Tracks, she's been performing across the globe and even collaborated with the Discovery Channel on an episode of Hello World. While it's easy to think wistfully of Xtina as the otherworldly voice from 2009's impossibly sensuous "Beautiful" video, it's clear the mom of two has cultivated a powerhouse career beyond the pop spotlight — even if it's still hard to escape the full-body nostalgia for her performance of "Reflection" in Disney's Mulan.

Fans took to Twitter on Monday to show their love for Aguilera's timeless talent, with one supporter even heaping compliments on Corden's vocal prowess. "James, you should be in Xtina's new album!!!!", one person wrote. No lie, singing next to Aguilera takes some serious guts. (Spoiler: If you're looking for proof, skip to the part where she tests how high her voice can go.)

The biggest takeaway from Aguilera's hilarious and harmonious Carpool Karaoke episode? Her pipes have undeniably stood the tests of the decades. "I've never heard a voice like it, oh my gosh," Corden mused as they pulled back into the studio lot after wrapping their cruise through early millennium pop gold. Considering he's belted behind-the-wheel tunes with Sam Smith, Harry Styles, and Jennifer Lopez, to name just a few, that feels like quite the compliment.