Corden headed to Las Vegas as part of his Late Late Show primetime special on Monday, and was joined by the Canadian diva, who was very excited to be a part of the beloved series.
"I just happen to have a day off once a year, and you called me on that day," Dion explained as she entered the car.
While Dion was more-than game to sing any tune Corden put on the radio, she also proved how she could take any song and add her own signature dramatic flair -- including the much-maligned "Baby Shark."
Despite not having heard the infamous tune before Dion belted out a stirring take that even included one of her famous chest-bumps.
Later -- after forcing Dion to give away some heels from her enormous collection of thousands of shoes -- Corden tried to get her to sing arguably her most famous song, "My Heart Will Go On," from the Titanic soundtrack.
After singing a few lines in his SUV, Corden shut off the radio and said that, if they were going to do that song, he wished it could be more epic, and Dion had the perfect idea.
Cut to: Dion and Corden standing in a recreation of the front of the Titanic, which was floating inside the Bellagio lake.
The pair sang their heart out to the amusement of hundreds of tourists as their performance was punctuated by a perfectly choreographed and timed presentation by the hotel's famous dancing fountains.
Those watching by the side of the Bellagio lake cheered loudly as Dion passionately dropped a recreation of the Heart of the Ocean necklace into the crystal clear waters below.
Dion's appearance on this special "Carpool Karaoke" might go down as one of the most spectacular in the history of the celebrated series.
ET's Nancy O'Dell spoke with Dion back in April, and asked about recreating the Titanic scene, which Corden had previously teased on Instagram.
"It was a crazy thing, you know, [but] it's fun to do fun things. It's a business that can be stressful," Dion said, before praising Corden. "I love him, he's so sweet. He's the best."
Earlier this month, Corden also gushed about filming the segment with Dion, telling ET, "I just was kind of thrilled to be in her orbit for a few minutes, you know? It was glorious. I'll never ever forget it."