Carpool Karaoke is James Corden's biggest bit by far. Big enough for its own primetime special, and big enough for George Clooney and Julia Roberts to muscle their way into the latest segment.

Corden spent some time with Gwen Stefani first, singing a few of her and No Doubt's hits (though, as always, my biggest complaint is that Corden's enthusiasm for singing along often drowns out his passenger, whose voice is the one we really want to hear) and talking about emojis. 

Then he found himself in an HOV lane that required four passengers, so he called on a friend with nothing better to do, who then called on his friend with nothing better to do, to help out. Also, they have a movie coming out soon but I'm sure that's just a coincidence. 

Anyway, the four belted out "Hollaback Girl" and then Queen's "We Are the Champions." Check it out: