Gwen Stefani has been performing since 1986, and over the years the 51-year-old has rocked so many incredible styles.MORE: Gwen Stefani makes surprising revelation about her first kisses with Blake SheltonOn Monday, the star shared an amazing throwback picture from the 1990s, and she looked completely unrecognisable.In the close-up shot, the Hollaback Girl singer was looking incredibly baby-faced while wearing a red polo shirt.WATCH: Gwen Stefani reveals how proposal nearly didn't happenGwen