James Corden Reveals Failed Prank On Adele During Final 'Carpool Karaoke': 'She's Unprankable'

James Corden has detailed his prank on Adele that didn't go as planned in the final episode of "The Late Late Show with James Corden."

Adele joined Corden for his final "Carpool Karaoke" segment. During their reunion, which aired Monday, the pals reflected on the unaired prank that the host tried to pull on the "Easy on Me" singer after she declared that "no one can ever prank me."

Corden, who was in the passenger seat this time around, explained to Adele their plans before the prank went wrong.

"I set up this whole thing — and to say it out loud now, it's so ridiculous — that there was a wild bear on the loose and we'd flown this animatronic bear from Canada," he shared.

Corden said his team had coordinated an interview with the singer at a house, where she would be interrupted by park rangers warning her that the bear was near.

To make the prank more convincing, the "Late Late Show" host worked with CBS News anchor Gayle King to record a fake news segment about the missing bear, which would be played in Adele's makeup room.

However, the prank quickly took a turn when someone from Adele's team, who had been unaware of the prank, spotted the hidden cameras and told the singer about it.

The "When We Were Young" hitmaker said she immediately thought at the time, "I'm being spied on." She started asking, "Who the f--k owns this house?"

However, things got worse when Adele entered the second room and found that it was filled with merch and photos of herself.

"Oh my God, no, I'm not happy being here, I'm really uncomfortable," she said in the never-before-seen footage.

Corden and his team noticed that the singer was already very uneasy and in distress so they decided to pull the plug on the joke.

Corden, who was wearing an officer's uniform, went out of the room next to where Adele was. The singer exclaimed, "You! You!" before they explained everything to her.

"She's unprankable! She cannot be pranked!" Corden said as Adele laughed. Then the duo started singing together.

Last April, Corden announced that after doing one more year, he would be leaving "The Late Late Show" following eight years as host of the CBS talk show.

"When I took the job -- firstly, I didn't think we'd be on the air, like, six months later. Then as soon as it seemed like we'd be on for a little while, I was very very determined that the show wouldn't overstay its welcome in any way and that we would always know when to leave," he explained to Entertainment Tonight.

Corden said that he wanted to explore other opportunities, adding: "You'll never find out [what is waiting for you] unless you just take a run and jump."