"It was a little awkward, like, driving by grocery stores. People walk by and there are like 18 cameras around us. This is just so awkward."
However, despite her reservations, Spears insisted she had fun.
She said: "Carpool Karaoke was really fun. The guy was just so incredibly sweet. I had no idea he has kids, he's a teddy bear. I was like, 'I just want to hug you right now.'"
And Spears even recreated her iconic Baby One More Time video, by donning her infamous school uniform as she belted out the hit.
The Late Late Show host got involved too, opting for a similar outfit, complete with a blonde plaited wig.
"You know your song, Oops! ... I Did It Again?" asked Corden. "What's that about? What's it REALLY about?"
"I don't know," Spears demurely replied innocently. "I think it's just a song."
"Because every time I order at Domino's," said Corden, "I think, 'Oops! I did it again!'"
The Piece of Me hitmaker also revealed she is "done" with men and no longer believes in marriage.
Spears - who was married to Jason Alexander for less than three days in 2004 and was also married to dancer Kevin Federline - said: "I think I might not do the whole men thing anymore. I won't do the men thing, or get married, I'm just done with men.
"I might French kiss someone but I'm not going to marry anyone - I don't believe in marriage anymore."
- Bang! Showbiz