The Voice coaches Blake Shelton and Gwen Stefani are engaged after dating for five years. Blake proposed to Gwen with what jewelry experts predict is a diamond approximately six to 10 carats in weight. Gwen gleefully showed off her brand new engagement ring when sharing their big news to fans on Tuesday. Of course, we won't know the exact details unless either Blake or Gwen decide to share them with the world. Regardless of the ring though, it's clear that Gwen and Blake, who have been dating since 2015, are both over the moon at the moment.