Before they belted out their hits, James got a little nosy about Nick's dating history: "So Nick you're dating seemingly everyone, and then who else?"
Demi gives her rundown of events: "Miley [Cyrus] and then Selena [Gomez] and then back with Miley."
"But this is all during the time that you're wearing the old purity ring...it's not anymore," Corden added. "So when did you decide to ditch the ring?"
Jonas replied, "I had a real relationship with an adult and I fell in love actually and I decided it was time for me to take it off...Are we gonna keep talking about my dating life?"
When the guys and gal sang Demi Lovato's Heart Attack, Demi really got a chance to wow with her voice.
Hailey Bieber's chin-grazing bob hairstyle is the inspiration you need to brave the chop