Britney Spears
Britney Spears appeared in the Carpool Karaoke segment back in 2016 to sing a few of her classics and talk about her life. James even asks her the hard hitting questions “What is ‘Oops I Did It Again’ about?” turns out – nothing, it’s just a song. The two even dress up in Britney’s classic school girl outfit to sing “Baby One More Time.”