James Corden sure knows how to throw a good Carpool Karaoke session—Gwen Stefani became his latest passenger in the popular The Late Late Show segment, and they had a real good time belting out some of her solo and No Doubt hit songs. And if that was not enough, they picked up two additional passengers on the way, making it a real star-studded edition. Yeap, Gwen Stefani, George Clooney and Julia Roberts in a car all at once—now this you can't miss. Want to watch Clooney sing along (every word) to "Hollaback Girl"? Watch it here: