If you would have told Gwen Stefani years ago that she would become a Grammy winner and a best-selling artist, she might not have believed you.
"I was just this girl from Orange County who was in a band with my friends," she revealed with amazement. "Then they kept letting me do more and more and more."
So when The Voice coach was asked to join MasterCard's Priceless Surprises campaign, the No Doubt singer knew she wanted to be a part of something equally as shocking.
"The biggest surprise in my career is that I have a career," she said in a behind-the-scenes video exclusively obtained by E! News.
In the clip, Stefani prepares to pay it forward by rewarding unsuspecting shoppers with priceless gifts including handbags, golf experiences and concert tickets.
"Who's ready for a surprise?" she asks while her new single "Spark the Fire" plays in the background.
What comes next is a slew of MasterCard cardholders who experience the shock of a lifetime. Whether being ambushed on a romantic date or during a father-son bonding trip, ordinary consumers are visibly surprised to find out they are big winners.
"I think the best part about surprising people is just making people happy," Stefani shares. "Bringing a smile to somebody's face and making their day. I like to do that."
So what happens when Stefani surprises a lucky fan in person? For that, you have to watch the video above!