One piece of advice Dion shared in the sneak peek came from her late husband, Rene Angelil, who also served as the songstress' talent manager for over three decades.
"My husband is always with me," Dion shared with Stefani and two contestants. "He said, 'You cannot be good all the time. You have to be good when it's time.'"
The time is coming soon for the excited contestants, as The Voice battle rounds kick off next week. Viewers will get to see just how much Dion -- as well as fellow mentors John Legend, DJ Khaled and Luke Bryan -- helped get them ready for the spotlight.
"She is so unique…. Every song she puts out is a world song, she speaks to the world and that's a whole other level [than], 'Oh I made it as a pop star in America,'" the No Doubt frontwoman shared. "She's [been] massive since she was 13 years old, so having her on the show was incredible." Check out the video below to hear more.