UPDATE: Britney did end up playing by the rules -- and actually sang during Thursday's "Carpool Karaoke." Watch her and James do "...Baby One More Time," with Corden in costume above!
We'll post the full video first thing Friday morning, once CBS uploads the entire clip to YouTube. For now, enjoy the performance above ... and Britney talking about spanking, bondage, marriage and swearing off men below!
Britney Spears will appear on Thursday night's episode of "The Late Late Show with James Corden" -- but, judging by a sneak peek at her "Carpool Karaoke" segment, she might be doing it wrong.
The CBS show released a short promo clip of Brit's appearance on the incredibly viral series, where famous celebs sing along to their songs -- as well as other popular singles -- while chit chatting with the Brit host in his car.
The only problem: Britney lip syncs.
As Corden rocks out to the pop star's "Toxic," Spears simply mimes along ... something anyone who's seen one of her concerts recently is probably used to.
Here's an example of how it's supposed to go down:
During another moment, Corden asks her whether her children, Sean Preston and Jayden James, have seen her Vegas show, "Piece of Me." "I saw my mom in her underwear once, when I was eleven," he deadpans. "You're so dirty!" Spears exclaims, delivering a good smack as she says it.
Hopefully, Brit Brit actually belts out a tune or two when the full segment airs Thursday on CBS. We'll be sure to update this post with the extended video once it's released!